Rising temperatures across the U.S. have reduced lake ice, sea ice, glaciers, and seasonal snow cover over the last several decades. Jump to “Arctic Sea Ice and Lake Ice is Melting”
Culture, Climate Science & Education
Click the Double Arrows () to Explore this Principle
Principle Eight: Climate Change will have Consequences
The Cultural Values are Courage, Compassion, and Endurance
Episode Eight: Wildfire
Episode 8: Wildfire
Transcript with Description of Visuals
|
Audio |
Visual |
|---|---|
|
Soft instrumental music: |
View from a helicopter flying into a steep, wooded canyon. The air is smoky, the far end of the canyon obscured by haze. |
|
I have grown up on this land, like my Sx̣epeʔ, and his Sx̣epeʔ before that. My name is Rylee. |
Rylee walking toward and then entering a blue helicopter. |
|
We're going into a wildfire to see how the climate affects a burning landscape. |
Helicopter taking off. |
|
With ever-increasing temperatures due to climate change, severe wildfires are becoming the new norm. |
Helicopter flying over forested mountains, columns of smoke rise from the trees. |
|
Ron Swaney, a fire management officer, has been fighting fire here for decades. He's seen firsthand how fire behavior has changed. |
Back on the ground, Ron Swaney, Rylee, and Rylee’s grandfather stand in front of a red and white fire-fighting airplane. Ron greets them and they shake hands. |
|
Ron Swaney: Three things that cause fires to spread: fuels, weather, and topography. And the only one that's the variable is the weather. We're getting hotter, we're getting drier, and the potential is only increasing for wildfire, based on just the climatology and the changes that have occurred. So it's been a dramatic change, both in the number of fires that we get and the amount of acres that we burn. |
Ron talks as Rylee and his grandfather listen. |
|
Rylee: |
Pilot of the plane sits in the cockpit, readying the plane for flight. Another man walks toward the plane and hands the pilot a bottle of water. |
|
My Sx̣epeʔ tells me how the tribes use fire as a tool to care for the land. |
Rylee’s grandfather taking to Rylee. |
|
The forests were kept healthy by thousands of years of burning by our ancestors. |
Black and white historical photo of two teepees set among the trees next to a lake. |
|
Rylee’s grandfather: Respect the fire, use it a good way, it'll help you. So with the huckleberries, the people knew this a long time ago. |
Rylee’s grandfather talking to Rylee. |
|
Rylee: |
Black and white historical photo of a group of Salish and Pend d’Oreille people on horses, two men in the foreground, dressed finely, look directly into the camera. |
|
The old ways are still relevant. |
Helicopter taking off and flying toward the mountains. |
|
What the Sx͏ʷpaam used to do they now call prescribed burns. They are the same thing. |
Rylee, wearing a helicopter flight helmet, looking out from the flying helicopter. The sky is filled with smoke. |
|
Fighting fires at a time of year when it will help the forest instead of hurting it. That makes dangerous fire less likely. |
View from the helicopter looking down at a line of fire burning through trees near a road. |
|
It is hard for us to imagine today, because for over 100 years, we have been trying to keep fire off the land. |
A firefighter in the helicopter looking down at the fire. |
|
The result is that the forests have grown dense, and are now much more prone to fire. |
View from the helicopter looking out at a tree covered mountain, crisscrossed with roads. Columns of smoke rise in multiple places from the mountain. The sky is filled with smoke. A more close-up view of the forest, smoke everywhere. |
|
We'll go into October, close to November, with very little moisture, elevated temperatures, and still quite a bit of fire potential. |
Ron Swaney talking to Rylee and Rylee’s grandfather. |
|
Rylee: |
Fire Fighting plane turning on the runway then taking off. |
|
I think we have a lot to learn by looking at how our ancestors used fire. |
Rylee and his grandfather smiling and laughing, a fire-fighting plane in the background. |
|
The land needs the help and knowledge that comes from thousands of years of living in this place. |
A high mountain lake, it’s waters a deep blue-green color. Scene transitions to a row of teepees in a grassy meadow. |
|
(soft instrumental music) |
The following credits in white text over a black background: |
Principle 8
What You Need to Know About Principle 8: Climate change will have consequences for the Earth system and human lives
The impacts of climate change on humans and the environment has become a focus for tribal, state, and federal governments, resource managers, medical professionals, emergency managers, insurance companies, military planners, and just about everybody else concerned about a livable, sustainable future.
Poverty, a lack of resources, and the absence of political will compound existing problems. Many feel that the challenge of the 21st century will be in preparing communities to adapt to climate change while reducing human impacts on the climate system (known as mitigation). Many jobs, if not entire industries, will emerge to address these complex issues. Indeed, our response to climate change presents tremendous opportunities for young people to make good money while making the world a better place to live.
click the tabs to open
Global Impacts
- Mean Global Temperatures are Increasing
The main impact of climate change is predicted to be an increase in global mean temperature over most land surfaces. We have already seen major changes. The sixteen warmest years on record have occurred in the last 17 years. Jump to “Mean Global Temperatures are Increasing”
- Arctic Sea and Lake Ice is Melting
- Sea Level is Rising and Coasts are Eroding
Melting of ice sheets and glaciers, combined with the thermal expansion of seawater as the oceans warm, is causing sea level to rise. Seawater is beginning to move onto low-lying land and cause billions of dollars in damage. Jump to “Sea Level is Rising”
- Changing Precipitation and Temperature are Altering the Distribution and Availability of Water and in Alaska, Permafrost is Thawing
Climate plays an important role in the global distribution of freshwater resources. Changing precipitation patterns and temperature conditions are changing the distribution and availability of freshwater. Winter snowpack and mountain glaciers are declining as a result of global warming. Jump to “Changing precipitation and temperature are altering the distribution and availability of water”
- Extreme Weather Events are Increasing
Incidents of extreme weather are increasing as a result of climate change. Many locations are seeing a substantial increase in the number of heat waves they experience per year and a decrease in episodes of severe cold. Precipitation events are becoming less frequent but more intense in many areas, and droughts are becoming more frequent and severe in areas where average precipitation is projected to decrease. Jump to “Extreme weather events are increasing”
- Oceans are Becoming more Acidic
The chemistry of ocean water is changed by absorption of carbon dioxide from the atmosphere. Increasing carbon dioxide levels in the atmosphere is causing ocean water to become more acidic, threatening the survival of shell-building marine species and the entire food web of which they are a part. Jump to “Oceans are Becoming More Acidic”
- Ecosystems are Changing
Ecosystems on land and in the ocean have been and will continue to be disturbed by climate change. Animals, plants, bacteria, and viruses will migrate to new areas with favorable climate conditions. Infectious diseases and certain species will be able to invade areas that they did not previously inhabit. Jump to “Ecosystems are Changing”
- Climate Change is Altering the Timing of Natural Events
There is now ample evidence that over the last decades, the phenology—the timing of seasonal activities such as timing of flowering or breeding —of many plant and animal species has advanced and that these shifts are related to climate change. Scientists are just now learning how these shifts in timing will impact living systems. Jump to “Climate Change is Altering the Timing of Natural Events”
- Human Health and Mortality Rates will be Affected
Human health and mortality rates will be affected to different degrees in specific regions of the world as a result of climate change. Although cold-related deaths are predicted to decrease, other risks are predicted to rise. The incidence and geographical range of climate-sensitive infectious diseases—such as malaria, dengue fever, and tick-borne diseases—will increase. Drought-reduced crop yields, degraded air and water quality, and increased hazards in coastal and low-lying areas will contribute to unhealthy conditions, particularly for the most vulnerable populations. Jump to “Human Health and Mortality Rates will be Affected”
- Summary of Impacts
Without action, climate scientists have warned that temperatures could rise by nearly 5° C above pre-industrial levels by 2100. World leaders meeting in Paris hope to keep average global surface temperature rises below 2° C – but their pledges to cut emissions could still see up to 3° C according to analyses. While it is very hard to make firm predictions, here are some of the potential impacts. All are for possible temperature rises occurring by 2100. Jump to “Summary of Impacts”
Alaska/Arctic Impacts
- Introduction
Alaska has warmed twice as fast as the rest of the nation, bringing widespread impacts. Sea ice is rapidly receding and glaciers are shrinking. Thawing permafrost is leading to more wildfire, and affecting infrastructure and wildlife habitat. Rising ocean temperatures and acidification will alter valuable marine fisheries. Open the “Introduction”
×Introduction
Alaska is the United States’ only Arctic region. Its marine, tundra, boreal (northern) forest, and rainforest ecosystems differ from most of those in other states and are relatively intact. Alaska is home to millions of migratory birds, hundreds of thousands of caribou, some of the world’s largest salmon runs, a significant proportion of the nation’s marine mammals, and half of the nation’s fish catch.
Energy production is the main driver of the state’s economy, providing more than 80% of state government revenue and thousands of jobs. Continuing pressure for oil, gas, and mineral development on land and offshore in ice-covered waters increases the demand for infrastructure, placing additional stresses on ecosystems. Land-based energy exploration will be affected by a shorter season when ice roads are viable, yet reduced sea ice extent may create more opportunity for offshore development. Climate also affects hydropower generation. Mining and fishing are the second and third largest industries in the state, with tourism rapidly increasing since the 1990s. Fisheries are vulnerable to changes in fish abundance and distribution that result from both climate change and fishing pressure. Tourism might respond positively to warmer springs and autumns but negatively to less favorable conditions for winter activities and increased summer smoke from wildfire.
Alaska is home to 40% (229 of 566) of the federally recognized tribes in the United States. The small number of jobs, high cost of living, and rapid social change make rural, predominantly Native, communities highly vulnerable to climate change through impacts on traditional hunting and fishing and cultural connection to the land and sea. Because most of these communities are not connected to the state’s road system or electrical grid, the cost of living is high, and it is challenging to supply food, fuel, materials, health care, and other services. Climate impacts on these communities are magnified by additional social and economic stresses. However, Alaskan Native communities have for centuries dealt with scarcity and high environmental variability and thus have deep cultural reservoirs of flexibility and adaptability.
Source: http://nca2014.globalchange.gov/report/regions/alaska - Observed and Projected Climate Change
Over the past 60 years, Alaska has warmed more than twice as rapidly as the rest of the United States, with state-wide average annual air temperature increasing by 3°F and average winter temperature by 6°F, with substantial year-to-year and regional variability. Open "Observed and Projected Climate Change”
×Observed Climate Change
Over the past 60 years, Alaska has warmed more than twice as rapidly as the rest of the United States, with state-wide average annual air temperature increasing by 3°F and average winter temperature by 6°F, with substantial year-to-year and regional variability. Most of the warming occurred around 1976 during a shift in a long-lived climate pattern (the Pacific Decadal Oscillation [PDO]) from a cooler pattern to a warmer one. The PDO has been shown to alternate over time between warm and cool phases. The underlying long-term warming trend has moderated the effects of the more recent shift of the PDO to its cooler phase in the early 2000s., The overall warming has involved more extremely hot days and fewer extremely cold days.
Because of its cold-adapted features and rapid warming, climate change impacts on Alaska are already pronounced, including earlier spring snowmelt, reduced sea ice, widespread glacier retreat, warmer permafrost, drier landscapes, and more extensive insect outbreaks and wildfire, as described below.Projected Climate Change
Average annual temperatures in Alaska are projected to rise by an additional 2°F to 4°F by 2050. If global emissions continue to increase during this century, temperatures can be expected to rise 10°F to 12°F in the north, 8°F to 10°F in the interior, and 6°F to 8°F in the rest of the state. Even with substantial emissions reductions, Alaska is projected to warm by 6°F to 8°F in the north and 4°F to 6°F in the rest of the state by the end of the century.
Figure 22.1: Alaska Will Continue to Warm Rapidly
Details/Download
Annual precipitation is projected to increase, especially in northwestern Alaska, as part of the broad pattern of increases projected for high northern latitudes. Annual precipitation increases of about 15% to 30% are projected for the region by late this century if global emissions continue to increase (A2). All models project increases in all four seasons. However, increases in evaporation due to higher air temperatures and longer growing seasons are expected to reduce water availability in most of the state.
The length of the growing season in interior Alaska has increased 45% over the last century and that trend is projected to continue. This could improve conditions for agriculture where moisture is adequate, but will reduce water storage and increase the risks of more extensive wildfire and insect outbreaks across much of Alaska., Changes in dates of snowmelt and freeze-up would influence seasonal migration of birds and other animals, increase the likelihood and rate of northerly range expansion of native and non-native species, alter the habitats of both ecologically important and endangered species, and affect ocean currents.
Source: http://nca2014.globalchange.gov/report/regions/alaska - Disappearing Sea Ice
Arctic summer sea ice is receding faster than previously projected and is expected to virtually disappear before mid-century. This is altering marine ecosystems and leading to greater ship access, offshore development opportunity, and increased community vulnerability to coastal erosion. Open “Disappearing Sea Ice”
×Disappearing Sea Ice
Arctic sea ice extent and thickness have declined substantially, especially in late summer (September), when there is now only about half as much sea ice as at the beginning of the satellite record in 1979. The seven Septembers with the lowest ice extent all occurred in the past seven years. As sea ice declines, it becomes thinner, with less ice build-up over multiple years, and therefore more vulnerable to further melting. Models that best match historical trends project northern waters that are virtually ice-free by late summer by the 2030s. Within the general downward trend in sea ice, there will be time periods with both rapid ice loss and temporary recovery, making it challenging to predict short-term changes in ice conditions.
Figure 22.2: Declining Sea Ice Extent
Details/Download
Reductions in sea ice increase the amount of the sun’s energy that is absorbed by the ocean. This leads to a self-reinforcing climate cycle, because the warmer ocean melts more ice, leaving more dark open water that gains even more heat. In autumn and winter, there is a strong release of this extra ocean heat back to the atmosphere. This is a key driver of the observed increases in air temperature in the Arctic., This strong warming linked to ice loss can influence atmospheric circulation and patterns of precipitation, both within and beyond the Arctic (for example, Porter et al. 2012). There is growing evidence that this has already occurred through more evaporation from the ocean, which increases water vapor in the lower atmosphere and autumn cloud cover west and north of Alaska.
With reduced ice extent, the Arctic Ocean is more accessible for marine traffic, including trans-Arctic shipping, oil and gas exploration, and tourism. This facilitates access to the substantial deposits of oil and natural gas under the seafloor in the Beaufort and Chukchi seas, as well as raising the risk to people and ecosystems from oil spills and other drilling and maritime-related accidents. A seasonally ice-free Arctic Ocean also increases sovereignty and security concerns as a result of potential new international disputes and increased possibilities for marine traffic between the Pacific and Atlantic Oceans.
Figure 22.3: Sea Ice Loss Brings Big Changes to Arctic Life
Details/Download
Polar bears are one of the most sensitive Arctic marine mammals to climate warming because they spend most of their lives on sea ice. Declining sea ice in northern Alaska is associated with smaller bears, probably because of less successful hunting of seals, which are themselves ice-dependent and so are projected to decline with diminishing ice and snow cover.,,, Although bears can give birth to cubs on sea ice, increasing numbers of female bears now come ashore in Alaska in the summer and fall and den on land. In Hudson Bay, Canada, the most studied population in the Arctic, sea ice is now absent for three weeks longer than just a few decades ago, resulting in less body fat, reduced survival of both the youngest and oldest bears, and a population now estimated to be in decline and projected to be in jeopardy. Similar polar bear population declines are projected for the Beaufort Sea region.
Walrus depend on sea ice as a platform for giving birth, nursing, and resting between dives to the seafloor, where they feed. In recent years, when summer sea ice in the Chukchi Sea retreated over waters that were too deep for walrus to feed,, large numbers of walrus abandoned the ice and came ashore. The high concentration of animals results in increased competition for food and can lead to stampedes when animals are startled, resulting in trampling of calves., This movement to land first occurred in 2007 and has happened three times since then, suggesting a threshold change in walrus ecology.
With the late-summer ice edge located farther north than it used to be, storms produce larger waves and more coastal erosion. An additional contributing factor is that coastal bluffs that were “cemented” by ice-rich permafrost are beginning to thaw in response to warmer air and ocean waters, and are therefore more vulnerable to erosion. Standard defensive adaptation strategies to protect coastal communities from erosion, such as use of rock walls, sandbags, and riprap, have been largely unsuccessful. Several coastal communities are seeking to relocate to escape erosion that threatens infrastructure and services but, because of high costs and policy constraints on use of federal funds for community relocation, only one Alaskan village has begun to relocate.
Living on the Front Lines of Climate Change
“Not that long ago the water was far from our village and could not be easily seen from our homes. Today the weather is changing and is slowly taking away our village. Our boardwalks are warped, some of our buildings tilt, the land is sinking and falling away, and the water is close to our homes. The infrastructure that supports our village is compromised and affecting the health and well-being of our community members, especially our children.”
Alaska Department of Commerce and Community and Economic Development, 2012
Figure 22.4: Newtok, Alaska
Details/Download
Newtok, a Yup’ik Eskimo community on the seacoast of western Alaska, is on the front lines of climate change. Between October 2004 and May 2006, three storms accelerated the erosion and repeatedly “flooded the village water supply, caused raw sewage to be spread throughout the community, displaced residents from homes, destroyed subsistence food storage, and shut down essential utilities.” The village landfill, barge ramp, sewage treatment facility, and fuel storage facilities were destroyed or severely damaged. The loss of the barge landing, which delivered most supplies and heating fuel, created a fuel crisis. Saltwater is intruding into the community water supply. Erosion is projected to reach the school, the largest building in the community, by 2017.
Recognizing the increasing danger from coastal erosion, Newtok has worked for a generation to relocate to a safer location. However, current federal legislation does not authorize federal or state agencies to assist communities in relocating, nor does it authorize them to repair or upgrade storm-damaged infrastructure in flood-prone locations like Newtok. Newtok therefore cannot safely remain in its current location nor can it access public funds to adapt to climate change through relocation.
Newtok’s situation is not unique. At least two other Alaskan communities, Shishmaref and Kivalina, also face immediate threat from coastal erosion and are seeking to relocate, but have been unsuccessful in doing so. Many of the world’s largest cities are coastal and are also exposed to climate change induced flood risks.
Source: http://nca2014.globalchange.gov/report/regions/alaska - Shrinking Glaciers
Most glaciers in Alaska and British Columbia are shrinking substantially. This trend is expected to continue and has implications for hydropower production, ocean circulation patterns, fisheries, and global sea level rise. Open “Shrinking Glaciers”
×Shrinking Glaciers
Alaska is home to some of the largest glaciers and fastest loss of glacier ice on Earth.,, This rapid ice loss is primarily a result of rising temperatures (for example, Arendt et al. 2002, 2009. Loss of glacial volume in Alaska and neighboring British Columbia, Canada, currently contributes 20% to 30% as much surplus freshwater to the oceans as does the Greenland Ice Sheet – about 40 to 70 gigatons per year, comparable to 10% of the annual discharge of the Mississippi River. Glaciers continue to respond to climate warming for years to decades after warming ceases, so ice loss is expected to continue, even if air temperatures were to remain at current levels. The global decline in glacial and ice-sheet volume is predicted to be one of the largest contributors to global sea level rise during this century.
Muir Glacier
At the top is a photograph of Muir Glacier in Alaska taken on August 13, 1941; beneath it, a photograph taken from the same vantage point on August 31, 2004. Total glacial mass has declined sharply around the globe, adding to sea level rise. (Left photo by glaciologist William O. Field; right photo by geologist Bruce F. Molnia of the United States Geological Survey.)
Water from glacial landscapes is also recognized as an important source of organic carbon,, phosphorus, and iron that contribute to high coastal productivity, so changes in these inputs could alter critical nearshore fisheries.
Glaciers supply about half of the total freshwater input to the Gulf of Alaska. Glacier retreat currently increases river discharge and hydropower potential in south central and southeast Alaska, but over the longer term might reduce water input to reservoirs and therefore hydropower resources.
Source: http://nca2014.globalchange.gov/report/regions/alaska - Thawing Permafrost
Permafrost temperatures in Alaska are rising, a thawing trend that is expected to continue, causing multiple vulnerabilities through drier landscapes, more wildfire, altered wildlife habitat, increased cost of maintaining infrastructure, and the release of heat-trapping gases that increase climate warming. Open “Thawing Permafrost”
×Thawing Permafrost
Alaska differs from most of the rest of the U.S. in having permafrost – frozen ground that restricts water drainage and therefore strongly influences landscape water balance and the design and maintenance of infrastructure. Permafrost near the Alaskan Arctic coast has warmed 4°F to 5°F at 65 foot depth, since the late 1970s and 6°F to 8°F at 3.3 foot depth since the mid-1980s. In Alaska, 80% of land is underlain by permafrost, and of this, more than 70% is vulnerable to subsidence upon thawing because of ice content that is either variable, moderate, or high. Thaw is already occurring in interior and southern Alaska and in northern Canada, where permafrost temperatures are near the thaw point. Models project that permafrost in Alaska will continue to thaw and some models project that near-surface permafrost will be lost entirely from large parts of Alaska by the end of the century.
Figure 22.5: Projections for average annual ground temperature at a depth of 3.3 feet over time if emissions of heat-trapping gases continue to grow (higher emissions scenario, A2), and if they are substantially reduced (lower emissions scenario, B1). Blue shades represent areas below freezing at a depth of 3.3 feet, and yellow and red shades represent areas above freezing at that depth, based on the GIPL 1.0 model. (Figure source: Permafrost Lab, Geophysical Institute, University of Alaska Fairbanks).
Uneven sinking of the ground in response to permafrost thaw is estimated to add between $3.6 and $6.1 billion (10% to 20%) to current costs of maintaining public infrastructure such as buildings, pipelines, roads, and airports over the next 20 years. In rural Alaska, permafrost thaw will likely disrupt community water supplies and sewage systems,,, with negative effects on human health. The period during which oil and gas exploration is allowed on tundra has decreased by 50% since the 1970s as a result of permafrost vulnerability.
Figure 22.6: Mounting Expenses from Permafrost Thawing
Details/Download
On average, lakes have decreased in area in the last 50 years in the southern two-thirds of Alaska due to a combination of permafrost thaw, greater evaporation in a warmer climate, and increased soil organic accumulation during a longer season for plant growth. In some places, however, lakes are getting larger because of lateral permafrost degradation. Future permafrost thaw will likely increase lake area in areas of continuous permafrost and decrease lake area in places where the permafrost zone is more fragmented.
A continuation of the current drying of Alaskan lakes and wetlands could affect waterfowl management nationally because Alaska accounts for 81% of the National Wildlife Refuge System and provides breeding habitat for millions of migratory birds that winter in more southerly regions of North America and on other continents. Wetland loss would also reduce waterfowl harvest in Alaska, where it is an important food source for Alaska Natives and other rural residents.
Figure 22.7: Drying Lakes and Changing Habitat
Details/Download
Both wetland drying and the increased frequency of warm dry summers and associated thunderstorms have led to more large fires in the last ten years than in any decade since record-keeping began in the 1940s. In Alaskan tundra, which was too cold and wet to support extensive fires for approximately the last 5,000 years, a single large fire in 2007 released as much carbon to the atmosphere as had been absorbed by the entire circumpolar Arctic tundra during the previous quarter-century. Even if climate warming were curtailed by reducing heat-trapping gas (also known as greenhouse gas) emissions (as in the B1 scenario), the annual area burned in Alaska is projected to double by mid-century and to triple by the end of the century, thus fostering increased emissions of heat-trapping gases, higher temperatures, and increased fires. In addition, thick smoke produced in years of extensive wildfire represents a human health risk (Ch. 9: Human Health). More extensive and severe wildfires could shift the forests of Interior Alaska during this century from dominance by spruce to broadleaf trees for the first time in the past 4,000 to 6,000 years.
Wildfire has mixed effects on habitat. It generally improves habitat for berries, mushrooms, and moose but reduces winter habitat for caribou because lichens, a key winter food source for caribou, require 50 to 100 years to recover after wildfire. These habitat changes are nutritionally and culturally significant for Alaska Native Peoples. In addition, exotic plant species that were introduced along roadways are now spreading onto river floodplains and recently burned forests,, potentially changing the suitability of these lands for timber production and wildlife. Some invasive species are toxic to moose, on which local people depend for food.
Changes in terrestrial ecosystems in Alaska and the Arctic may be influencing the global climate system. Permafrost soils throughout the entire Arctic contain almost twice as much carbon as the atmosphere. Warming and thawing of these soils increases the release of carbon dioxide and methane through increased decomposition. Thawing permafrost also delivers organic-rich soils to lake bottoms, where decomposition in the absence of oxygen releases additional methane. Extensive wildfires also release carbon that contributes to climate warming. The capacity of the Yukon River Basin in Alaska and adjacent Canada to store carbon has been substantially weakened since the 1960s by the combination of warming and thawing of permafrost and by increased wildfire. Expansion of tall shrubs and trees into tundra makes the surface darker and rougher, increasing absorption of the sun’s energy and further contributing to warming. This warming is likely stronger than the potential cooling effects of increased carbon dioxide uptake associated with tree and shrub expansion.
The shorter snow-covered seasons in Alaska further increase energy absorption by the land surface, an effect only slightly offset by the reduced energy absorption of highly reflective post-fire snow-covered landscapes. This spectrum of changes in Alaskan and other high-latitude terrestrial ecosystems jeopardizes efforts by society to use ecosystem carbon management to offset fossil fuel emissions.
Source: http://nca2014.globalchange.gov/report/regions/alaska - Changing Ocean Temperatures and Chemistry
Current and projected increases in Alaska’s ocean temperatures and changes in ocean chemistry are expected to alter the distribution and productivity of Alaska’s marine fisheries, which lead the U.S. in commercial value. Open “Changing Ocean Temperatures and Chemistry”
×Changing Ocean Temperatures and Chemistry
Ocean acidification, rising ocean temperatures, declining sea ice, and other environmental changes interact to affect the location and abundance of marine fish, including those that are commercially important, those used as food by other species, and those used for subsistence. These changes have allowed some near-surface fish species such as salmon to expand their ranges northward along the Alaskan coast. In addition, non-native species are invading Alaskan waters more rapidly, primarily through ships releasing ballast waters and bringing southerly species to Alaska. These species introductions could affect marine ecosystems, including the feeding relationships of fish important to commercial and subsistence fisheries.
Overall habitat extent is expected to change as well, though the degree of the range migration will depend upon the life history of particular species. For example, reductions in seasonal sea ice cover and higher surface temperatures may open up new habitat in polar regions for some important fish species, such as cod, herring, and pollock. However, continued presence of cold bottom-water temperatures on the Alaskan continental shelf could limit northward migration into the northern Bering Sea and Chukchi Sea off northwestern Alaska. In addition, warming may cause reductions in the abundance of some species, such as pollock, in their current ranges in the Bering Sea and reduce the health of juvenile sockeye salmon, potentially resulting in decreased overwinter survival. If ocean warming continues,it is unlikely that current fishing pressure on pollock can be sustained. Higher temperatures are also likely to increase the frequency of early Chinook salmon migrations, making management of the fishery by multiple user groups more challenging.
The changing temperature and chemistry of the Arctic Ocean and Bering Sea are likely changing their role in global ocean circulation and as carbon sinks for atmospheric CO2 respectively, although the importance of these changes in the global carbon budget remains unresolved. The North Pacific Ocean is particularly susceptible to ocean acidification. Acidifying changes in ocean chemistry have potentially widespread impacts on the marine food web, including commercially important species.
Ocean Acidification in Alaska
Ocean waters globally have become 30% more acidic due to absorption of large amounts of human-produced carbon dioxide (CO2) from the atmosphere. This CO2 interacts with ocean water to form carbonic acid that lowers the ocean’s pH (ocean acidification). The polar ocean is particularly prone to acidification because of low temperature, and low salt content, the latter resulting from the large freshwater input from melting sea ice and large rivers. Acidity reduces the capacity of key plankton species and shelled animals to form and maintain shells and other hard parts, and therefore alters the food available to important fish species. The rising acidity will have particularly strong societal effects on the Bering Sea on Alaska’s west coast because of its high-productivity commercial and subsistence fisheries.
Shelled pteropods, which are tiny planktonic snails near the base of the food chain, respond quickly to acidifying conditions and are an especially critical link in high-latitude food webs, as commercially important species such as pink salmon depend heavily on them for food. A 10% decrease in the population of pteropods could mean a 20% decrease in an adult pink salmon’s body weight. Pteropod consumption by juvenile pink salmon in the northern Gulf of Alaska varied 45% between 1999 and 2001, although the reason for this variation is unknown.
At some times of year, acidification has already reached a critical threshold for organisms living on Alaska’s continental shelves. Certain algae and animals that form shells (such as clams, oysters, and crab) use carbonate minerals (aragonite and calcite) that dissolve below that threshold. These organisms form a crucial component of the marine food web that sustains life in the rich waters off Alaska’s coasts. In addition, Alaska oyster farmers are now indirectly affected by ocean acidification impacts farther south because they rely on oyster spat (attached oyster larvae) from Puget Sound farmers who are now directly affected by the recent upwelling of acidic waters along the Washington and Oregon coastline.
Source: http://nca2014.globalchange.gov/report/regions/alaska - Native Communities
The cumulative effects of climate change in Alaska strongly affect Native communities, which are highly vulnerable to these rapid changes but have a deep cultural history of adapting to change. Open “Native Communities”
×Native Communities
With the exception of oil-producing regions in the north, rural Alaska is one of the most extensive areas of poverty in the U.S. in terms of household income, yet residents pay the highest prices for food and fuel. Alaska Native Peoples, who are the most numerous residents of this region, depend economically, nutritionally, and culturally on hunting and fishing for their livelihoods. Hunters speak of thinning sea and river ice that makes harvest of wild foods more dangerous changes to permafrost that alter spring run-off patterns, a northward shift in seal and fish species, and rising sea levels with more extreme tidal fluctuations. Responses to these changes are often constrained by regulations., Coastal erosion is destroying infrastructure. Impacts of climate change on river ice dynamics and spring flooding are threats to river communities but are complex, and trends have not yet been well documented.
Figure 22.8: Alaska Coastal Communities Damaged
Details/Download
Major food sources are under stress due to many factors, including lack of sea ice for marine mammals. Thawing of near-surface permafrost beneath lakes and ponds that provide drinking water cause food and water security challenges for villages. Sanitation and health problems also result from deteriorating water and sewage systems, and ice cellars traditionally used for storing food are thawing. Warming also releases human-caused pollutants, such as poleward-transported mercury and organic pesticides, from thawing permafrost and brings new diseases to Arctic plants and animals, including subsistence food species, posing new health challenges, especially to rural communities., Positive health effects of warming include a longer growing season for gardening and agriculture.
Development activities in the Arctic (for example, oil and gas, minerals, tourism, and shipping) are of concern to Indigenous communities, from both perceived threats and anticipated benefits. Greater levels of industrial activity might alter the distribution of species, disrupt subsistence activities, increase the risk of oil spills, and create various social impacts. At the same time, development provides economic opportunities, if it can be harnessed appropriately.
Alaska Native Elders say, “We must prepare to adapt.” However, the implications of this simple instruction are multi-faceted. Adapting means more than adjusting hunting technologies and foods eaten. It requires learning how to garner information from a rapidly changing environment. Permanent infrastructure and specified property rights increasingly constrain people’s ability to safely use their environment for subsistence and other activities.
Traditional knowledge now facilitates adaptation to climate change as a framework for linking new local observations with western science.,,, The capacity of Alaska Natives to survive for centuries in the harshest of conditions reflects their resilience. Communities must rely not only on improved knowledge of changes that are occurring, but also on support from traditional and other institutions – and on strength from within – in order to face an uncertain future.
Source: http://nca2014.globalchange.gov/report/regions/alaska
Principle 8a
Mean Global Temperatures are Increasing
The main impact of climate change is predicted to be an increase in global mean temperature over most land surfaces. We have already seen major changes. The table at left below lists the sixteen warmest years from 1880 to 2015. Note that all have occurred in the last 17 years. The animated chart at right below shows a rainbow-colored record of global temperatures spinning outward from the late 19th century to the present as the Earth heats up. Read more…
The New Normal
NOAA publishes climatological normals every decade based on 30-year average temperatures; the most recent normals are based on the average temperatures from 1981-2010. Expanding on this dataset, Climate Central calculated a 30-year average ending each year from 1980 to 2015. For example, the normal temperature for 1980 in this analysis was based on the average temperature from 1951-1980, and the 2015 normal is the average from 1986-2015.
Of the 135 locations analyzed, 97 percent of them had a higher 30-year average temperature in 2015 versus 1980, and many have seen an additional surge in their normals since the last NOAA analysis in 1981-2010. The shift in long term averages has already become apparent in the longer growing season in most of the country, with temperatures starting to remain consistently above freezing earlier in the year, and staying above freezing until later in the year. Some plant and animal species are starting to migrate northward or upward in elevation as a result, meaning a variety of pests and weeds are now found in places previously too cold for them to live.
While the warming of the normals can look subtle, it also means a substantial increase in the incidents of extreme heat and a decrease in the frequency of extreme cold. Winters have been warming more rapidly than summers, and while less extreme cold sounds appealing, the future effects of blistering summer heat are expected to outweigh the benefits of milder winters. More extreme heat will increase the threat of heat-related illness such as heat stroke. In addition, this expansion of very hot days will stress the nation’s aging electric grid, driving up cooling costs as air conditioners will likely be used more frequently.
Source: http://www.climatecentral.org/gallery/graphics/the-new-normal-earth-is-getting-hotter
What is Projected for Alaska and the Arctic?
Heating Up
Over the past 60 years, Alaska has warmed more than twice as rapidly as the rest of the United States. Though the state experiences substantial year-to-year and regional variability, state-wide average annual air temperature has increased by 3°F, and average winter temperatures have risen by 6°F. Because of the rapid warming observed across the state, climate change impacts on Alaska are already pronounced; they include earlier spring snowmelt, reduced sea ice, widespread glacier retreat, warmer permafrost, drier landscapes, and more extensive insect outbreaks and wildfire.
Long-term average temperature (green) compared to daily observations (blue) at Kotzebue, Alaska, for January 2013 through July 2015. The graph reveals the highly variable and often extreme weather (especially in winter) that is common in Alaska and the Arctic.
If global emissions continue to increase through this century, climate scientists project that average temperatures in Alaska will rise up to 12°F in the north, 10°F in the interior, and 8°F in the rest of the state. Even with substantial reductions in emissions, climate models project that average temperatures across the state will warm by at least 5°F by the end of the century.
These maps show projected temperature changes across Alaska in the early, middle, and late parts of this century relative to 1971–1999. The top row shows projections for a scenario in which emissions of heat-trapping gases continue to increase (higher emissions, A2); the bottom row shows a scenario in which emissions are substantially reduced (lower emissions, B1).
Average annual precipitation is also projected to increase, especially in northwestern Alaska, as part of the broad pattern of increases projected for high northern latitudes. If global emissions continue their current trend, annual precipitation is projected to increase by 15 to 30 percent by late this century. All models project increases in precipitation for all four seasons. However, increases in evaporation due to higher air temperatures and longer growing seasons are also expected, and these may reduce water availability across large portions of the state.
The length of the growing season in interior Alaska has increased 45 percent over the average length of the growing season in the last century, and climate scientists expect this trend to continue. Longer growing seasons could improve conditions for agriculture where moisture is adequate. Additional potential consequences of climate change in Alaska include a decrease in available water, an increase in the risk of extensive wildfires, and increased insect outbreaks.
What About the Rest of the Country?
Think It’s Hot Now? Just Wait
By HEIDI CULLEN AUG. 20, 2016
Source: http://www.nytimes.com/interactive/2016/08/20/sunday-review/climate-change-hot-future.html?_r=0
Heat waves have become more frequent, more intense and longer lasting. A study in the journal Nature Climate Change last year found that three of every four daily heat extremes can be tied to global warming. The maps below provide a glimpse of our future if nothing is done to slow climate change. By the end of the century, the number of 100-degree days will skyrocket, making working or playing outdoors unbearable, and sometimes deadly. The effects on our health, air quality, food and water supplies will get only worse if we don’t drastically cut greenhouse gas emissions right away.
Click on the maps to enlarge them.
Mean Global Temperatures are Increasing
The main impact of climate change is predicted to be an increase in global mean temperature over most land surfaces. We have already seen major changes. The table at left below lists the sixteen warmest years from 1880 to 2015. Note that all have occurred in the last 17 years. The animated chart at right below shows a rainbow-colored record of global temperatures spinning outward from the late 19th century to the present as the Earth heats up.
Climate models are fairly consistent in projecting the continuation of this trend through the 21st century. According to the Intergovernmental Panel on Climate Change (IPCC), temperatures are likely to increase by 2°F to 11.5°F, with a best estimate of 3.2°F to 7.2°F, by 2100, relative to 1980–1990 temperatures.
As a consequence of the increases we have already seen, glaciers have shrunk, ice on rivers and lakes is breaking up earlier, plant and animal ranges have shifted and trees are flowering sooner.
Effects that scientists had predicted in the past would result from global climate change are now occurring: loss of sea ice, accelerated sea level rise and longer, more intense heat waves. In the future we will see more droughts and heat waves, hurricanes will become stronger, sea level will rise, the Arctic will become ice free.
"Taken as a whole," the IPCC states, "the range of published evidence indicates that the net damage costs of climate change are likely to be significant and to increase over time."
What are our Possible Temperature Futures?
The Consequences: What We Can Expect
-
Increase of Less than 2 °C
Arctic sea icecap disappears, leaving polar bears homeless and changing the Earth's energy balance dramatically as reflective ice is replaced during summer months by darker sea surface. Now expected by 2030 or even earlier.
Tropical coral reefs suffer severe and repeated bleaching episodes due to hotter ocean waters, killing off most coral and delivering a hammer blow to marine biodiversity.
Droughts spread through the sub-tropics, accompanied by heatwaves and intense wildfires. Worst-hit are the Mediterranean, the south-west United States, southern Africa and Australia. -
2 °C to 3 °C
Summer heatwaves such as that in Europe in 2003, which killed 30,000 people, become annual events. Extreme heat sees temperatures reaching the low 40s Celsius in southern England.
Amazon rainforest crosses a "tipping point" where extreme heat and lower rainfall makes the forest unviable - much of it burns and is replaced by desert and savannah.
Dissolved CO2 turns the oceans increasingly acidic, destroying remaining coral reefs and wiping out many species of plankton which are the basis of the marine food chain. Several metres of sea level rise is now inevitable as the Greenland ice sheet disappears. -
3 °C to 4 °C
Glacier and snow-melt in the world's mountain chains depletes freshwater flows to downstream cities and agricultural land. Most affected are California, Peru, Pakistan and China. Global food production is under threat as key breadbaskets in Europe, Asia and the United States suffer drought, and heatwaves outstrip the tolerance of crops.
The Gulf Stream current declines significantly. Cooling in Europe is unlikely due to global warming, but oceanic changes alter weather patterns and lead to higher than average sea level rise in the eastern US and UK. -
4 °C to 5 °C
Another tipping point sees massive amounts of methane - a potent greenhouse gas - released by melting Siberian permafrost, further boosting global warming. Much human habitation in southern Europe, north Africa, the Middle East and other sub-tropical areas is rendered unviable due to excessive heat and drought. The focus of civilisation moves towards the poles, where temperatures remain cool enough for crops, and rainfall - albeit with severe floods - persists. All sea ice is gone from both poles; mountain glaciers are gone from the Andes, Alps and Rockies.
-
5 °C to 6 °C
Global average temperatures are now hotter than for 50m years. The Arctic region sees temperatures rise much higher than average - up to 20C - meaning the entire Arctic is now ice-free all year round. Most of the topics, sub-tropics and even lower mid-latitudes are too hot to be inhabitable. Sea level rise is now sufficiently rapid that coastal cities across the world are largely abandoned.
-
6 °C and Above
Danger of "runaway warming", perhaps spurred by release of oceanic methane hydrates. Could the surface of the Earth become like Venus, entirely uninhabitable? Most sea life is dead. Human refuges now confined entirely to highland areas and the polar regions. Human population is drastically reduced. Perhaps 90% of species become extinct, rivalling the worst mass extinctions in the Earth's 4.5 billion-year history.
Source: http://www.theguardian.com/environment/2009/apr/14/climate-change-environment-temperature
Heating Up: A Dangerous Spiral
This graphic, drawn up by Ed Hawkins, a climate scientist at the University of Reading in the United Kingdom, features a record of global temperatures spinning outward from the late 19th century to the present as the Earth heats up. The graphic displays monthly global temperature data, specifically how each month compares to the average for the same period from 1850-1900. At first, the years vacillate inward and outward, showing that a clear warming signal had yet to emerge from the natural fluctuations that happen from year to year. But clear warming trends are present in the early and late 20th century.
Can you determine about what year temperatures really started to rise?
So, the Earth's average temperature has increased about 1 degree Fahrenheit during the 20th century. What's the big deal?
One degree may sound like a small amount, but it's an unusual event in our planet's recent history. Small changes in temperature correspond to enormous changes in the environment. For example, at the end of the last ice age, when the Northeast United States was covered by more than 3,000 feet of ice, average temperatures were only 5 to 9 degrees cooler than today.
Now look at the spiral below, which shows simulated global temperature change from 1850 up to 2100 relative to the 1850 - 1900 average (how old will you be in the year 2100?). The temperature data are from Community Climate System (CCSM4) global climate model maintained by the National Center for Atmospheric Research. The simulation is for the IPCC Representative Concentration Pathway 8.5 (RCP8.5) emission scenario. RCP8.5 is the most aggressive scenario in which green house gases continue to rise unchecked through the end of the century, leading to an equivalent of about 1370 ppm CO2, which is roughly four times the concentration at present.
The Ten Hottest Years on Record
Source: NASA GISS & NOAA NCEI global temperature anomalies (°F) averaged and adjusted to early industrial baseline (1881-1910). Data as of 2/6/2019. The prediction of NASA and international climate scientists is for the trend to continue and even accelerate. For example, eighty years from now, the mean global temperature is expected to be 7 to 11 °F warmer than it is today.
Principle 8b
Arctic Sea and Lake Ice is Melting
Melting Ice
Rising temperatures across the U.S. have reduced lake ice, sea ice, glaciers, and seasonal snow cover over the last few decades. In the Great Lakes, for example, total winter ice coverage has decreased by 63% since the early 1970s. This includes the entire period since satellite data became available. When the record is extended back to 1963 using pre-satellite data, the overall trend is less negative because the Great Lakes region experienced several extremely cold winters in the 1970s. Read more…
Source: National Climate Assessment
Use the slider bar on the image to compare the extension of older sea ice in the Arctic in September 1984 and September 2016 (note: it may take a moment for the slider to appear).
Credit: NASA Earth Observatory
Melting Ice
Sea ice in the Arctic has also decreased dramatically since the late 1970s, particularly in summer and autumn. Since the satellite record began in 1978, minimum Arctic sea ice extent (which occurs in early to mid-September) has decreased by more than 40%. This decline is unprecedented in the historical record, and the reduction of ice volume and thickness is even greater. Ice thickness decreased by more than 50% from 1958-1976 to 2003-2008, and the percentage of the March ice cover made up of thicker ice (ice that has survived a summer melt season) decreased from 75% in the mid-1980s to 45% in 2011. Recent analyses indicate a decrease of 36% in autumn sea ice volume over the past decade. The 2012 sea ice minimum broke the preceding record (set in 2007) by more than 200,000 square miles.
Ice loss increases Arctic warming by replacing white, reflective ice with dark water that absorbs more energy from the sun. More open water can also increase snowfall over northern land areas and increase the north-south meanders of the jet stream, consistent with the occurrence of unusually cold and snowy winters at mid-latitudes in several recent years.
The loss of sea ice has been greater in summer than in winter. The Bering Sea, for example, has sea ice only in the winter-spring portion of the year, and shows no trend in surface area covered by ice over the past 30 years. However, seasonal ice in the Bering Sea and elsewhere in the Arctic is thin and susceptible to rapid melt during the following summer.
The seasonal pattern of observed loss of Arctic sea ice is generally consistent with simulations by global climate models, in which the extent of sea ice decreases more rapidly in summer than in winter. However, the models tend to underestimate the amount of decrease since 2007. Projections by these models indicate that the Arctic Ocean is expected to become essentially ice-free in summer before mid-century under scenarios that assume continued growth in global emissions, although sea ice would still form in winter. Models that best match historical trends project a nearly sea ice-free Arctic in summer by the 2030s, and extrapolation of the present observed trend suggests an even earlier ice-free Arctic in summer. However, even during a long-term decrease, occasional temporary increases in Arctic summer sea ice can be expected over timescales of a decade or so because of natural variability. The projected reduction of winter sea ice is only about 10% by 2030, indicating that the Arctic will shift to a more seasonal sea ice pattern. While this ice will be thinner, it will cover much of the same area now covered by sea ice in winter.
Source: National Climate Assessment
The Arctic is a Seriously Weird Place Right Now
- Published: November 21st, 2016
- Source: http://www.climatecentral.org/news/arctic-sea-ice-record-low-20903
By Brian Kahn
The sun set on the North Pole more than a month ago, not to rise again until spring. Usually that serves as a cue for sea ice to spread its frozen tentacles across the Arctic Ocean. But in the depths of the polar night, a strange thing started to happen in mid-October. Sea ice growth slowed to a crawl and even started shrinking for a bit.
Intense warmth in both the air and oceans is driving the mini-meltdown at a time when Arctic sea ice should be rapidly growing. This follows last winter, when temperatures saw a huge December spike.
Sea ice extent using JAXA satellite measurements.
Credit: Zack LabeEven in an age where climate change is making outliers — lowest maximum sea ice extent set two years in a row, the hottest year on record set three years in a row, global coral bleaching entering a third year — the norm, what’s happening in the Arctic right now stands out for just how outlandish it is.
“I’ve never seen anything like it this last year and half,” Mark Serreze, director of the National Snow and Ice Data Center, said.
The latest twist in the Arctic sea ice saga began in mid-October. Temperatures stayed stuck in their September range, pausing sea ice growth. By the end of the month, the Arctic was missing a chunk of ice the size of the eastern U.S.
| RELATED | Warm Temps Slow Arctic Sea Ice Growth to a Crawl |
The oddness continued into November. A large area of the Arctic saw temperatures as much as 36°F above normal, further slowing Arctic sea ice growth and even turning it around for a few days. In other words, it was so warm in the Arctic that despite the lack of sunlight, sea ice actually disappeared.
“ The ridiculously warm temperatures in the Arctic during October and November this year are off the charts over our 68 years of measurements,” Jennifer Francis, a climate scientist at Rutgers University who studies the Arctic, said.
Compounding the warm air is warm water. Sea surface temperatures on the edge of the ice are also running well above normal in many places, further inhibiting sea ice growth.
As a footnote, Antarctic sea ice is also record low, making for a really dire global sea ice graph. The two regions’ current conundrums aren’t connected, and researchers are still trying to untangle what’s happening there. But in the Arctic, a number of factors — both driven by climate change and weather patterns — are to blame for this year’s bizarre sea ice situation.
Global sea ice extent is also at a record low.
Credit: WipneusFirst, Arctic sea ice itself has some issues. Old ice has all but disappeared since record keeping began in the 1980s, and the majority of the ice pack is now young ice that tends to be more brittle and prone to breakup when extreme warmth strikes.
Some of that warmth came courtesy of the tropics where convection patterns created a series of large troughs and ridges in the atmosphere. The pattern that set up in mid-October put the eastern edge of one of these troughs over northeast Asia, according to Paul Roundy, an atmospheric scientist at the University of Albany.
Before
Drag split-screen slider or click on before/after link.
After
A comparison of the extension of older sea ice in the Arctic in September 1984 and September 2016.
Credit: NASA Earth Observatory
“The result has been a strong surface low that has funneled warm air at the surface across the Bering Strait,” he said. “A similar low set up in the wave train over the North Atlantic, providing another pathway for warmth into the Arctic.”
The ocean heat has roots in this summer, when dark open water absorbed the sun’s incoming energy (compared to white sea ice, which reflects it back into space). Francis said this “not only slowed the freezing process, but also warmed and moistened the air. That extra moisture is very important because water vapor is a greenhouse gas and it also tends to create more clouds — both of these effects help trap heat near the surface.” It’s what Serreze said was a “double whammy” of warming causing the current meltdown.
This all follows what was the second-lowest sea ice extent ever recorded in September and what has been a persistent dwindling of Arctic sea ice for decades on end as climate change cranks up the heat.
The Arctic is warming twice as fast as the rest of the planet and it’s possible that the region could see ice-free summers as early as the 2030s. If carbon pollution continues at its current pace, it would likely make ice-free summers the norm by mid-century.
Going forward, Serreze said research should focus as on how an already changing Arctic system responds to these types of shocks.
“A valuable way of viewing Arctic system now is (looking at) how it responds to these extremes. Has their impact changed now that Arctic has changed?” he said.
S
Arctic Oceans, Sea Ice, and Coasts
The impacts of reduced sea ice include severe and coastal erosion, isolation for rural villages and reduced habitat for wildlife
Source: https://toolkit.climate.gov/topics/arctic/arctic-oceans-sea-ice-and-coasts
The Arctic Ocean is blanketed by seasonal sea ice that expands during the frigid Arctic winter, reaching a maximum average extent each March. Sea ice retreats during the Northern Hemisphere's summer, reaching its minimum extent for the year every September. Arctic ice cover plays an important role in maintaining Earth’s temperature—the shiny white ice reflects light and the net heat that the ocean would otherwise absorb, keeping the Northern Hemisphere cool.
Arctic sea ice extent in September 2012 was the lowest in the satellite record (since 1979). The magenta line indicates the September average ice extent from 1981 to 2010.
Arctic sea ice is declining at an increasing rate in all months of the year, with a stronger decline in summer months. Researchers who study climate and sea ice expect that, at some point, the Arctic Ocean will lose virtually all of its late summer ice cover. A robust range of evidence suggests that Arctic sea ice is declining due to climate warming related to the increased abundance of heat-trapping (greenhouse) gases in the atmosphere from human burning of coal, oil, and gas. Because greenhouse gases stay in the atmosphere for multiple decades, scientists do not expect any reversal in the downward trend in ice extent.
Despite year-to-year variations, satellite data show a decline of more than 13 percent per decade in September ice extent since the satellite record began in 1979. The satellite data are less comprehensive before 1979, but shipping records and other evidence show that the ice extent has been in a continued state of decline for at least the last one hundred years. Climate models have long predicted that summer sea ice would disappear as temperatures rose in the Arctic, but ice loss has occurred even faster than any models predicted. Researchers now expect that the Arctic Ocean will be virtually ice-free in summer well before the end of this century, perhaps as early as the 2030s.
Impacts of reduced sea ice
Arctic amplification refers to the magnified warming in the Arctic relative to the rest of the globe—the rate of warming in the Arctic is nearly two times the global average. While a number of mechanisms contribute to Arctic amplification, the loss of Arctic sea ice cover plays a dominant role due to the reduction in the net albedo—a measure of how well a surface reflects incoming solar energy.
In 2012, the Parry Channel—a portion of the long-sought Northwest Passage—went from ice-choked on July 17 (left) to open water on August 3 (right). Sea ice reflects most of the sunlight energy that hits it back into space; open water can absorb heat energy from the sun.
White or light-colored sea ice is very reflective, so its albedo is higher than that of ocean water. With the huge increase in the area of ice-free water compared to a decade ago, the ocean can absorb much more heat than it used to. This, in turn, means that more heat energy is available to be released back into the atmosphere in autumn as sunlight wanes. As ice cover shrinks, areas of open water absorb heat that the ice would have reflected. The water warms up, and before ice can form again in the fall the ocean must release some of that heat to the atmosphere. Scientists are concerned that this increased heat transfer to the atmosphere could magnify future climate warming trends.
S
Principle 8c
Sea Level is Rising and Coasts are Eroding
Melting of ice sheets and glaciers, combined with the thermal expansion of seawater as the oceans warm, is causing sea level to rise. There is strong evidence that global sea level is now rising at an increased rate and will continue to rise during this century.
While studies show that sea levels changed little from AD 0 until 1900, sea levels began to climb in the 20th century.
The two major causes of global sea-level rise are thermal expansion caused by the warming of the oceans (since water expands as it warms) and the loss of land-based ice (such as glaciers and polar ice caps) due to increased melting. Read more…
Sea Level is Rising and Coasts are Eroding
Records and research show that sea level has been steadily rising at a rate of 0.04 to 0.1 inches per year since 1900. This rate may be increasing. Since 1992, new methods of satellite altimetry (the measurement of elevation or altitude) indicate a rate of rise of 0.12 inches per year. This is a significantly larger rate than the sea-level rise averaged over the last several thousand years.
Seawater is beginning to move onto low-lying land and to contaminate coastal fresh water sources and beginning to submerge coastal facilities and barrier islands. Sea-level rise increases the risk of damage to homes and buildings from storm surges such as those that accompany hurricanes.
Sea-level rise, along with the loss of sea ice in the Arctic, exposes shorelines to rapid coastal erosion. For most of the year, landfast sea ice buffered Alaska's northern coastline from waves, winds, and currents. Current observations and future projections of melt and sea level rise show that as sea ice melts earlier and forms later in the year, Arctic coasts will be more vulnerable to storm surge and wave energy. Particularly in the autumn, when large storms are occur in the region, land is exposed to shoreline erosion and terrestrial habitat loss.
Click the button below for a summary of how coastal erosion is affecting Alaska
Alaska Region
Climate Change: Realities of Relocation for Alaska Native Villages
Source: http://www7.nau.edu/itep/main/tcc/Tribes/ak_inupiaqnw_rel
Introduction:
As temperatures across the Arctic rise at twice the global average, the impacts of climate change in Alaska are already being felt (IPCC 2007). Warming temperatures exacerbate problems of permafrost erosion, flooding, and melting ice barriers, making an already unpredictable environment even more volatile (GAO 2004). Alaska Natives are among the most impacted in this region, and, according to the Government Accountability Office (2004), flooding and erosion affects 86% of Alaska Native villages to some extent.
As a consequence of the changing living conditions, Alaska Native communities are being forced to relocate their homes in what is called the first wave of U.S. climate refugees (Sakakibara 2010), reflecting the war-like effects of climate change. However, relocating is a culturally damaging, expensive, and politically complex process that only a few villages have begun. While a small number of Alaska Native communities are considering relocation, the situation continues to worsen: in a 2004 report, the GAO reported that flooding and erosion imminently threatened four villages. By 2009, that number had risen to thirty-one villages.
Rock revetment project, Kivalina, Alaska. Source: Millie Hawley, Manager Kivalina Environmental Program.
Understanding Relocation:
Extreme weather in Alaska is not a new phenomenon, and Alaska Natives are accustomed to adapting to its effects. Traditionally, many communities would adapt to the seasonal variability by migrating between hunting grounds throughout the year. However, beginning around the turn of the 20th century, Alaska Natives were forced to settle by the U.S. government, creating a dependence on the immediate area and subsequent vulnerability to events like erosion and flooding (MOVE 2010). Climate change creates more extreme seasonal events, increasing the risk associated with living in one place, including erosion of permafrost foundations on which many communities are built (GAO 2009, pg 7).
Alaska Native communities are at varying stages in considering relocation, and have very different perspectives of what relocation will mean. While some individuals may look forward to improved living conditions (New York Times 2007), others are reluctant to abandon the lands their ancestors lived on for thousands of years (Powering A Nation 2010). The primary efforts of Alaska Natives, however, are often focused on securing food and shelter for their families, making planning for long-term changes more challenging.
In 2009, the GAO reported that 12 of 31 communities identified as imminently threatened had decided to relocate. The GAO reported that these communities were at varying stages in the process, and slowed down by a number of challenges, including choosing a relocation site, paying for the process, and partnering with government organizations. Additionally, uprooting and moving to a new land represents breaking from uniquely adapted traditions that took thousands of years to develop (BBC News).
The situation is complicated further by finding a site that is both culturally acceptable and structurally sound. Alaska Native communities are located in some of the most remote places in the world, and are often only accessible by airplane (GAO 2009). As a result, the cost of relocating several hundred people climbs into the hundreds of millions. The U.S. Army Corps of Engineers estimated the cost of relocating Kivalina at $95-125 million, Shishmaref at $100-200 million, and Newtok at $80-130 million. These costs are well beyond what is realistic for subsistence communities, so most turn to government agencies for funding support. Unfortunately, there are a myriad of political, cultural and economic factors that complicate obtaining government funding for relocation. For example, the USACE has to justify its projects by performing a cost evaluation that shows that expected benefits outweigh the cost (GAO 2004). However, estimating the cost of preserving some of the oldest cultures in the world is very complex.
Another complication arises from Alaska’s political jurisdictions: " Because of Alaska’s unique structure of organized boroughs and an unorganized borough, unincorporated Native villages in the unorganized borough do not qualify for federal housing funds from HUD’s (U.S. Department of Housing and Urban Development) Community Development Block Grant program. The disqualification of the villages in this borough is not because they lack the need for these funds, but because there is no local government that is a political subdivision of the state to receive the funds" (GAO 2009). Even funding specifically aimed to address these types of situations is sometimes unavailable to communities: "The Federal Emergency Management Agency has several disaster preparedness and recovery programs, but villages often fail to qualify for them, generally because they may lack approved disaster mitigation plans or have not been declared federal disaster area " (GAO 2009).
Agency Support:
Owing to the economic and technical dynamics of relocation, communities are reaching out to government organizations for assistance. The State of Alaska is addressing the need for such assistance and in 2007 created the Climate Change Sub-Cabinet, which has participated in the preparation and implementation of a climate change strategy for Alaska. Information made available on the State of Alaska climate change website (www.climatechange.alaska.gov/) addresses adaptation, mitigation, immediate actions and research needs. At the Federal level, the U.S. Army Corps of Engineers has been working closely with communities to help develop strategies and provide technical support for relocation. However, the lack of a lead federal entity to coordinate and help prioritize assistance to relocating villages creates many problems with miscommunication and undirected efforts (GAO 2009).
Alaska Native Villages Engaged in Relocation Efforts:
A 2004 report from the Government Accountability Office (GAO) identified 31 Alaska Native Villages as &imminently threatened."
Source: 2004 GAO report, pg 18
In 2009, the GAO listed 12 communities that had begun exploring relocation options: Kivalina, Newtok, Shishmaref, Shaktoolik, Allakaket, Golovin, Hughes, Huslia, Koyukuk, Nulato, Teller, and Unalakleet (GAO 2009). Following are highlights from efforts by three of these villages to explore relocation, as well as links to more in-depth resources and case studies about these communities.
Kivalina:
Located on an island in the northwest corner of Alaska, the village of Kivalina is quickly losing the ice that governs life for its 400 residents. The ice provides a natural barrier against harsh sea storms, serves as the community’s hunting ground for seals, and gives the village its drinking water. The Army Corps of Engineers estimated relocation costs to be $95 - $125 million (ACE 2006). Kivalina experienced further struggles in identifying a relocation site. "The Community has identified a site it wishes to move to, but that the USACE does not believe is an adequate site, e.g. it is underlain with permafrost which would require many feet of fill material to provide a good foundation for buildings" (IAW 2009).
According to Mille Hawley, President of the Kivalina IRA Council, the community has shifted its focus from relocation to evacuation. The community decided on the change because evacuation is something that state and federal agencies can support more easily than relocation, and a strong evacuation plan will keep people safe. To accomplish this, the village of Kivalina is currently utilizing Bureau of Indian Affairs funds for roads to develop a plan to build a bridge from the island to the mainland. The village hopes to access additional funding and foster partnerships with entities including the Denali Commission, the Army Corps of Engineers and the Coast Guard to develop a comprehensive evacuation plan. Hawley suggested that focusing on individual activities, such as development of an evacuation plan, may be more likely to result in incremental changes that will help keep the people of Kivalina safe. More information on relocation efforts in Kivalina can be found at www.kivalinacity.com/ and www.cakex.org/case-studies/2773.
Shishmaref:
Inhabited for over 4,000 years, the town of Shishmaref is located on a barrier island in the Chukchi Sea off the western coast of Alaska. Shishmaref depends on the ice surrounding the island for protection, food, and water. In recent decades, Shishmaref has lost 40% of the ice that protects it from storm surges reaching the island, and already more than 10 homes have had to be evacuated (Spanner Films 2001). Shishmaref began exploring relocation in 2001, and in 2002 formed the Shishmaref Erosion and Relocation Coalition comprised of the governing members of the city, Indian Reorganization Council, and the Shishmaref Native Corporation Board of Directors. The Army Corps of Engineers estimated relocation costs to be $100 - $200 million (ACE 2006). More information on Shishmaref can be found at: www.shishmarefrelocation.com and www.cakex.org/case-studies/2770.
Newtok:
Located on the western coast of Alaska, Newtok is home to 320 Alaska Natives. The sea and the river that cuts through Newtok are eroding the permafrost on which the town is built. A 1983 assessment of erosion problems found that within 25 to 30 years, the erosion would begin to endanger the community. Since then, Newtok has worked on relocation efforts, and in 1994 started the relocation planning process. By 1996, the town had selected Mertaryik, which in Yup'ik means "getting water from the spring," as the relocation site. The Army Corps of Engineers estimated relocation costs to be $80 to $130 million (ACE 2006). In 2006, the Newtok community, government agencies, and non-governmental organizations formed the Newtok Planning Group, which was described in the 2009 IAWG Report as "a model for local community, state and federal partnerships to address complex issues." More information on Newtok relocation efforts can be found at www.commerce.state.ak.us/dca/planning/npg/Newtok_Planning_Group.htm or www.cakex.org/case-studies/1588.
Research Efforts on Relocation in Alaska:
Moved by the State: Perspectives on Relocation and Resettlement in the Circumpolar North (MOVE) is a project of the European Science Foundation and funded by the Canadian Social Sciences and Humanities Research Council, the US National Science Foundation, the Academy of Finland, and the Danish Research Agency. It is a research initiative comprised of five participating projects based in Canada (University of Alberta), Finland (University of Lapland), Denmark (University of Greenland), and the United States (University of Alaska Fairbanks & University of Maryland). Over a four-year project lifespan, field research involving teams of researchers and local collaborators will be conducted in Alaska, northern Canada, Greenland and regions of the Russian far North (Chukotka, Magadan, Yamal). MOVE has conducted research to date in Kivalina in partnership with faculty at the University of Alaska in Fairbanks, and is currently performing fieldwork in Shishmaref and Koyukuk (MOVE 2010).
References
For references go to: http://www7.nau.edu/itep/main/tcc/Tribes/ak_inupiaqnw_rel
For a good summary of climate change impacts on sea level rise, visit the National Climate Assessment
Visualizing Our Changing Coastlines
See how rising sea levels will affect North America's coast under different global warming conditions. You can use the Search icon (the magnifying glass) to type in any coastal location you may be interested in. Be patient, the visualization tool can take a few minutes to load, depending on your internet connection (if it's taking too long try clicking here to go to the Surging Seas Risk Finder and enter your zip code).
Be sure to scroll down in the window below to learn more.
United States
Sea level is on the rise. Since 1900, it's gone up an average of eight inches around the world, due to global warming. And by 2100, it will be higher still — maybe as high as six-and-a-half feet above 1992 levels. That would put the homes of 7.8 million Americans at risk of being flooded.
Sea level rise: Global warming's yardstick
By Rosalie Murphy,
NASA's Jet Propulsion Laboratory
Source: http://climate.nasa.gov/news/2201/
One of the Argo array’s buoys begins collecting ocean temperature data after a science team deploys it in the Atlantic Ocean. Credit: Argo / University of California, San Diego.
Global sea levels have been ticking steadily higher by about an eighth of an inch (3.2 millimeters) each year since scientists began measuring them two decades ago. That’s why Carmen Boening, a research scientist at NASA’s Jet Propulsion Laboratory in Pasadena, California, was so shocked in 2010 and 2011, when she saw a quarter-inch (five-millimeter) drop in sea level – a sudden reversal of the trend.
“We knew that either the sea was cooling, or there was less water in the ocean,” Boening said. Like metal, water contracts when it cools. “So we used NASA’s GRACE mission, which basically weighs water to tell us how much is present in different parts of the world, both in the ocean and on land. We found there was actually less water in the ocean.”
Water can’t just vanish. If it leaves the ocean, it has to show up somewhere else in the water cycle. Sure enough, Boening’s team found huge amounts of precipitation and flooding in Australia and South America. GRACE data suggested lots of water had evaporated from the ocean during the 2011 La Niña event. Then other wind patterns pushed the precipitation to Australia.
“It had to be a combination of all these events at once, and that’s why the drop was so large,” Boening said. “But at some point, it had to run off into the ocean. That’s what happened next.” A few months later, the ocean returned to the previous year’s levels and the upward trend resumed.
How NASA measures sea level
Global sea levels have risen by about 8 inches in the last 130 years. It might not sound like much – but the ocean covers about 70 percent of Earth’s surface and holds about 99 percent of its water. A tiny rise or fall involves a lot of water.
“Sea level rise is the yardstick for global warming,” said Josh Willis, a research scientist at JPL. “It’s the ruler by which we measure how much human activity has changed the climate. It’s the sum of the extra heat the ocean has absorbed and the water that’s melted off of glaciers and ice sheets.” 
The Ocean Surface Topography Mission (OSTM)/Jason-2 measures sea surface height. Credit: NASA
Willis leads NASA’s Jason missions, satellites that measure sea level and ocean surface topography, or variations in ocean surface height at different areas around the globe. This variation is driven in part by deeper currents and weather patterns like El Niño, La Niña and the Pacific Decadal Oscillation. These patterns move huge amounts of water from some regions of the ocean to others, pushing some parts of the surface downward and others upward.
The GRACE twin satellites make detailed measurements of Earth's gravity field. Credit: NASA
The Gravity Recovery and Climate Experiment (GRACE) mission, which helped Boening and Willis track water during the 2011 La Niña, collects data using twin satellites orbiting Earth together. When the lead satellite encounters a slight change in Earth’s gravity, the force pulls it a little further from its partner. The second satellite measures the distance between them to estimate the strength of Earth’s gravity.
The planet’s gravity changes because different amounts of mass have piled up at different places. There’s a lot more Earth in the Himalaya, for example, than in the Mississippi Delta. Similarly, when water coalesces in a certain part of the ocean, it tugs on GRACE’s satellites a little harder.
But changes on land also play a role. For example, Greenland’s ice is melting. "As the land loses mass, its gravitational pull is not as strong, so it’s losing its ability to attract water,” Boening said. Though melting land ice from Greenland and glaciers account for about two-thirds of sea level rise to date, “sea level around Greenland is actually going down.”
Mass, height and heat
The ocean is also gaining heat. Small heat transfers happen constantly at the ocean’s surface and, eventually, the ocean swallows most of the heat greenhouse gases have trapped in Earth’s atmosphere. That heat warms the whole ocean, causing it to expand.
Expansion seems simple, but measuring it is a challenge. “Over 90 percent of the heat trapped inside Earth’s atmosphere by global warming is going into the oceans,” Willis said. Temperature data from 19th-century ship, compared to a set of 3,600 buoys measuring ocean temperature today, confirms that the ocean – especially its upper half – has warmed since 1870.
In the bottom half of the ocean, though, it’s harder to tell. Buoys measure only about halfway to the bottom, a depth of about 1.25 miles (2,000 meters). Over many decades, ocean currents pull water from the surface of the ocean toward its depths. Scientists have assumed the deep ocean has been warming, too – but a new paper by Willis and other JPL scientists found no detectable warming below that 1.25-mile (2,000-meter) mark since 2005.
“We can’t see heat in the deep ocean yet. The effect has been too small over our ten years of data, and the ways the ocean can get heat down deep are very slow. It might take a hundred years,” Willis said. “We still have to rely on the data and not our simulations to figure out what’s going on in the deep ocean. So we have some more scientific work to do.”
On the other hand, another paper from the same journal found that earlier studies drastically underestimated warming in the Southern Ocean, since the 1970s. New estimates suggest it absorbed anywhere from 25 to 58 percent more heat than previous researchers thought.
Scientists will continue learning more about the ocean’s intricacies, correcting assumptions and revising old estimates. But Willis warns against losing sight of the strong global trend toward rising sea levels.
“The picture is very simple,” he said. “The ocean heats up and causes sea level rise. Ice melts and causes sea level rise. We can see the results at the shoreline.”
This feature is part of a series exploring how NASA monitors Earth’s water cycle. Other ocean missions include Aquarius, which measures the ocean’s salinity to offer scientists clues about evaporation and rainfall patterns and changes in the ocean’s density, which can drive circulation patterns. The Surface Water and Ocean Topography (SWOT) mission will improve topography measurements at the coast after its 2020 launch. Learn more about all of NASA’s Earth science missions.
S
Principle 8d
Changing precipitation and temperature are altering the distribution and availability of water, and in Alaksa, permafrost is thawing
Climate plays an important role in the global distribution of freshwater resources. Changing precipitation patterns and temperature conditions will alter the distribution and availability of freshwater resources, reducing reliable access to water for many people and their crops. Read more…
Changing precipitation and temperature are altering the distribution and availability of water. In Alaska, permafrost is thawing.
Winter snowpack and mountain glaciers that provide water for human use are declining as a result of global warming. There are many unknowns in terms of how ecosystems and societies will be impacted by the loss of snow and ice which serve as reservoirs of freshwater.
In permafrost zones of Alaska, summer thaw near the surface creates an “active layer” of thawed soil above the permanently frozen soil below. As climate warms, the season when the permafrost surface is active becomes longer and warmer, causing the active layer to become deeper or the entire permafrost layer to thaw. This change lets water infiltrate deeper into the ground, causing hydrologic changes that affect the kinds of vegetation that can grow.
Runoff patterns are shifting in many parts of the world with more rain and less snow falling as precipitation.
Learn about changing temperature and precipitation patterns in Alaska
Melting Glaciers, Snow, and Ice
Rising temperatures are chaining processes that control the buildup and melt of snowpack, the growth or decline of glaciers, and the timing of quantity of streamflow in the Arctic.
Source: https://toolkit.climate.gov/regions/alaska-and-arctic/melting-glaciers-snow-and-ice
Climate change is expected to affect where, when, and how much snow and ice occur on the landscape. Changes in temperature and precipitation—reflected in trends over many decades and in variability from seasons to decades—alter fundamental physical processes of the region. Such altered processes include the buildup and melt of snowpacks, the growth or decline of glaciers, and the timing and quantity of hydrologic processes, such as streamflow. The impact of climate change on snow and ice depends on what time frame is considered, how local weather and climate respond to hemispheric or global changes in temperature and precipitation, and, at finer scales, how these changes play out over the complex and rugged topography of the region. Some of these changes are intuitive, particularly for snowpack; however, the complex interaction between topography, elevation, and broad-scale weather patterns may lead to some unexpected dynamics for glaciers.
Climate change and its effects on snow, ice, and hydrology
Climate—the statistics of weather over time (usually 30 years or more)—can be considered as the combination of temperature, precipitation, wind, the nature of storms, atmospheric pressure, and other factors characteristic of a place. Climate also includes the interannual to decadal (and longer) variability in those characteristics and the regional to global mechanisms that cause it. However, the characteristic climate in Alaska and the Arctic is changing rapidly in ways that are explainable only by global climate change. Projecting possible climate impacts on snow and ice processes requires understanding the mechanisms by which weather and climate affect snowpack, glaciers, and resulting streamflow.
In places where snow and ice were historically common, changes in climate can be expected to affect snowpack development, distribution, and melt as temperature increases and the timing and quantity of precipitation change. Increasing temperature impacts snowpack directly by affecting both the seasonal timing of snowmelt and the period of the year that is cool enough to promote snowpack accumulation.
Glacial environments from ice field to ocean. (a) Glacier runoff emanating from the terminus of Mendenhall Glacier, Alaska. (b) Meares Glacier terminus and fjord, Prince William Sound, Alaska, showing forested hillslopes above the glacier. (c) Mixing of ocean and silt-laden water in Berners Bay, Alaska. (d) Mother and pup harbor seals hauled-out on icebergs calved from McBride Glacier, Glacier Bay National Park, Alaska.
First, as average temperatures during autumn, winter, and spring become warmer, the likelihood that storms will occur while temperatures are above freezing increases, leading to an increase in the amount of precipitation that falls as rain instead of snow. Second, as spring temperatures increase, spring melt occurs earlier in the year. Despite increased temperature, increased precipitation may result in substantial increases of snow at very high elevations, where precipitation was less abundant in the past, but future temperatures are projected to be rarely above freezing. At colder locations where temperature is consistently below freezing (usually at higher elevations or in the interior), increased future precipitation could result in increased snowpack.
On average, high-latitude snowmelt now occurs earlier in the spring. Snowcover returns later in the fall and covers a smaller area than in the past. Together, this loss of snowcover reduces terrestrial albedo (how well a surface reflects incoming solar energy), increases the amount of heat absorbed by the land, and contributes to high-latitude warming.
Glaciers
Glaciers are the result of a climate that consistently produces more snowfall during winter than can be melted in summer. The surplus of snow accumulates over decades to millennia and eventually compacts into ice. As the ice deepens, the glacier’s immense weight causes the ice to flow downhill until it reaches lower elevations, which are warmer and receive less snowfall, thus allowing the excess ice to melt.
The top photo shows Pederson Glacier on the Kenai Peninsula of southeastern Alaska in 1917. The bottom photo, taken from the same vantage point, shows what was left of the glacier in 2005. Around the globe, total glacial mass has declined sharply, adding to sea level rise.
A glacier can maintain a constant size and shape if the net gain of snow in its upper accumulation zone perfectly offsets the net amount of ice lost in the lower ablation zone (melt zone). If the amount of melt exceeds the amount of snow accumulation, the mass budget of the glacier becomes negative and the glacier will shrink, adding that water to streamflow and, eventually, the oceans. The size of glaciers is thus inextricably linked to the relative amounts of snowfall and melt—two factors that are expected to change with a changing climate. Most high-latitude glaciers are shrinking and contributing more water to streamflow.
Collectively, the changes in snow and ice with climate change can be expected to have impacts on the hydrology of systems both within and downstream from mountains and glaciers. These hydrologic changes can in turn have significant impacts on—and be influenced by—terrestrial, riparian, and coastal ecosystems. Geology and geography, along with the physical and ecological changes in watersheds, affect the response of hydrography to climate change, so responses can vary significantly from watershed to watershed within a region. There are also strong ice-ocean-ecosystem linkages and feedbacks, including nutrient delivery and primary productivity, which have implications for fish and bird populations.
Permafrost and Arctic Landscapes
As the climate warms, portions of “permanently” frozen ground are beginning to thaw, changing how water interacts with the land and reducing the stability of soils beneath buildings, homes, and roads.
Source: https://toolkit.climate.gov/regions/alaska-and-arctic/permafrost-and-arctic-landscapes
Permafrost (permanently frozen ground) in the Arctic is highly variable geographically because differences in climate, topography, and soil properties interact in different ways to affect its formation and persistence. As latitude increases, the likelihood of continuous permafrost also increases, while at lower latitudes (such as interior Alaska) areas of permafrost may have intervals or gaps.
In permafrost zones, summer thaw near the surface creates an “active layer” of thawed soil above the permanently frozen soil below. Below the active layer, the permanent ice that fills pore spaces between soil particles limits water infiltration. As climate warms, the season when the permafrost surface is active becomes longer and warmer, causing the active layer to become deeper or the entire permafrost layer to thaw. As this change lets water infiltrate deeper into the ground, hydrologic changes occur. These changes, in turn, affect the kinds of vegetation that can grow on the land's surface because different types of plants need different levels of soil moisture and depth to permafrost.
This satellite view of a site on the Siberian tundra near Russia's Yenisey River in 1966 (left) shows much more open tundra than a view of the same area in 2009 (right).
Changing permafrost can also contribute to the observed increase in the extent and severity of forest and tundra fires—deeper water drainage allows surface fuels to dry. Both wetland drying and the increased frequency of warm, dry summers have led to more large fires in the last ten years than in any decade since record keeping began in the 1940s. Wildfire can have mixed effects on habitat: it generally improves habitat for some species, but it reduces habitat for caribou because lichens, a key winter caribou habitat, require 50 to 100 years to recover after wildfire.
Landscape change in the Arctic under climate change is therefore a complex process. Interactions between permafrost, hydrology, vegetation, and disturbance are already occurring, but the nature and permanence of these changes varies from place to place with local factors, so the impacts vary considerably. In some coastal regions, the changes in permanently frozen ground interact with changes in sea ice and storminess to create novel conditions for dramatically increased rates of coastal erosion. In interior Alaska, effects of permafrost thaw can present challenges for infrastructure by reducing the stability of soils beneath buildings, homes, and roads.
Good summaries of impacts on freshwater can be found in the National Climate Assessment
Despite Gains, Western Snowpack Trending Downward in the Continental U.S.
Western Snowpack Trending Downward
By Climate Central
The first of April is the end of the wet season across the West, the time of year when the region gets most of its precipitation. As such, it is a good time to take inventory of the snowpack in the mountains. The snow readings are important during this time of the year, as several locations depend on the meltwater from that snowpack for drinking water and irrigation through the drier and hotter summer months. It also serves as a long-term measurement, as in a warming world, the spring snowpack will melt more quickly as summer nears.
While the western snowpack levels have improved over last year’s dismally low levels overall, there are still places below average in Colorado, Montana, and New Mexico.
Learn about projected impacts on Alaska's infrastructure
Climate Change is Hell on Alaska's Formerly Frozen Highways
A critical artery is threatened by thawing permafrost.
August 2, 2016
Greg Quinn
Source: http://www.bloomberg.com/news/features/2016-08-02/the-alaskan-highway-is-literally-melting
Snowcapped mountains and evergreens along the Alaska Highway.
For seven decades, the Alaska Highway has mesmerized adventure-seeking travelers. In one breathtaking stretch through the Yukon, glacier lakes and rivers snake through aspen forests and rugged mountains that climb into the clouds.
In recent years, though, a new sight has been drawing motorists’ attention, too, one they can spot just a few feet from their cars’ tires. Bumps and cracks have scarred huge swathes of the road, with some fissures so deep a grown man can jump in and walk through them. Scientists say they’re the crystal-clear manifestation that permafrost -- slabs of ice and sediment just beneath the Earth’s surface in colder climes -- is thawing as global temperatures keep rising.
In some parts of the 1,387-mile (2,232 kilometer) highway, the shifting is so pronounced, it has buckled parts of the asphalt. Caution flags warn drivers to slow down, while engineers are hard at work concocting seemingly improbable solutions: inserting plastic cooling tubes or insulation sheets, using lighter-colored asphalt or adding layers of soccer-ball sized rocks -- fixes that are financially and logistically daunting.
Illustration: Sam Dodge for Bloomberg
“It’s the single biggest geotechnical problem we have,” said Jeff Currey, materials engineer for the northern region of Alaska’s Department of Transportation. “The Romans built roads 2,000 years ago that people are still using. On the other hand, we have built roads that within a year or two, without any maintenance, look like a roller coaster because they are built over thaw-unstable permafrost.”
At the time of its construction, the highway was a show of American ingenuity and determination during World War II. In March 1942, just months after the Japanese bombed Pearl Harbor, the U.S. Army hastily began to build a road linking Alaska, another exposed Pacific outpost, through Canada to the lower 48 states. Seven months later it was opened, providing a key supply line in case of invasion.
Today the highway serves as the main artery connecting the “Last Frontier” with Canada and the northwestern U.S., bringing tourists to Alaska cruise ships; food, supplies and medicine to remote towns; and equipment to oil fields and mines that are the region’s lifeblood.
Judy Gagnon, a 67-year-old trucker, has driven Canada’s roads since the early 1970s and said she’s seeing “more pieces fall apart.” Some damage is regular wear and tear, but “they are having trouble maintaining the road bed, because you have the permafrost underneath, and then you have it melting and it’s sinking.”
The highway’s dark surface absorbs sunlight while the shoulders trap water and snow that act like a warm blanket. The heat breaks down the permafrost (soil, rock or sediment frozen for at least two consecutive years). Annual repair costs for one section that runs through the Yukon are C$30,000 ($22,900) per kilometer, seven times the average, according to a territorial government report.
Thawing also threatens airport runways, buildings, animal-migration patterns and energy pipelines. It's a problem outside North America, too. More than 600 scientists from nations including the U.S., Canada, Russia, China, Sweden, and Argentina, attended an international permafrost conference in June.
The 341st Engineer Regiment at work on the Alaska Highway around 1942.
Source: Courtesy Office of History, U.S. Army Corps of Engineers
The Alaska Highway challenged its original builders seven decades ago by swallowing up trucks. Any digging caused some terrain to thaw unless extra layers of logs and gravel were installed on top to ensure that “the frost was permanently locked in,” according to a 1944 U.S. War Department film.
Today’s engineers don’t assume permafrost will remain stable, even with modern insulation. Some roads being built now may become lost causes, requiring new bridges or detours, if global warming exceeds estimates in upgraded building standards.
“There are so few roads, and there is no redundancy, so every road is critical,” Currey said. “A detour is possible, but the detour might be 700 miles.”
Forty-three percent of a 124-mile stretch between Alaska and Whitehorse, the Yukon capital, is “highly vulnerable to permafrost thaw,” according to a report co-authored by Fabrice Calmels, a researcher at Yukon College.
“It’s like taking five stories out of a 10-story building,” he said in an interview.
One solution is to keep heat away by building thicker embankments with larger gravel and rocks that help circulate cooler air, or by adding layers of insulation such as foam. More expensive options include installing pipes to vent out warmth. Some vents, called thermosyphons, are tubes, often filled with liquid carbon dioxide, that use a cycle of evaporation and condensation to take advantage of cooler air temperatures. These work if the difference above and below ground is at least 1 degree Celsius.
The key is creating infrastructure that’s “resilient” to future changes, said Paul Murchison, director of transportation engineering at the Yukon Department of Highways and Public Works.
Paul Murchison, director of transportation engineering at the Yukon Department of Highways and Public Works, stands inside a rift caused by permafrost melting.
Source: Courtesy Yukon Research Centre and College
Mark Carney, governor of the Bank of England, and Canada’s Environment and Climate Change Minister Catherine McKenna stressed the urgency of the problem at a July 15 discussion on global warming. McKenna gave a grim update on Carney’s birthplace in the Northwest Territories, just east of the Yukon.
“Communities are unable to reach each other, it’s harder to get goods there,” she told attendees in Toronto. Thawing permafrost isn’t “just an inconvenience, folks; it’s a change in the way of life.”
Q
Principle 8e
Extreme Weather Events are Increasing
Incidents of extreme weather are projected to increase as a result of climate change—indeed they already have increased and are projected to increase much more. Many locations will see a substantial increase in the number of heat waves they experience per year and a decrease in episodes of severe cold. Precipitation events are expected to become less frequent but more intense in many areas, and droughts will be more frequent and severe in areas where average precipitation is projected to decrease. Explore the graphics on this page to see how things have already changed.
Arctic Weather and Extreme Events
Alaska is warming much faster than the rest of the country, and extreme weather events are occurring more often. Click the button below to learn more.
Arctic Weather and Extreme Events
Source: https://toolkit.climate.gov/regions/alaska-and-arctic/arctic-weather-and-extreme-events
Over the past 60 years, Alaska has warmed more than twice as rapidly as the rest of the United States. Though the state experiences substantial year-to-year and regional variability, state-wide average annual air temperature has increased by 3°F, and average winter temperatures have risen by 6°F. Because of the rapid warming observed across the state, climate change impacts on Alaska are already pronounced; they include earlier spring snowmelt, reduced sea ice, widespread glacier retreat, warmer permafrost, drier landscapes, and more extensive insect outbreaks and wildfire.
Long-term average temperature (green) compared to daily observations (blue) at Kotzebue, Alaska, for January 2013 through July 2015. The graph reveals the highly variable and often extreme weather (especially in winter) that is common in Alaska and the Arctic.
If global emissions continue to increase through this century, climate scientists project that average temperatures in Alaska will rise up to 12°F in the north, 10°F in the interior, and 8°F in the rest of the state. Even with substantial reductions in emissions, climate models project that average temperatures across the state will warm by at least 5°F by the end of the century.
These maps show projected temperature changes across Alaska in the early, middle, and late parts of this century relative to 1971–1999. The top row shows projections for a scenario in which emissions of heat-trapping gases continue to increase (higher emissions, A2); the bottom row shows a scenario in which emissions are substantially reduced (lower emissions, B1).
Average annual precipitation is also projected to increase, especially in northwestern Alaska, as part of the broad pattern of increases projected for high northern latitudes. If global emissions continue their current trend, annual precipitation is projected to increase by 15 to 30 percent by late this century. All models project increases in precipitation for all four seasons. However, increases in evaporation due to higher air temperatures and longer growing seasons are also expected, and these may reduce water availability across large portions of the state.
The length of the growing season in interior Alaska has increased 45 percent over the average length of the growing season in the last century, and climate scientists expect this trend to continue. Longer growing seasons could improve conditions for agriculture where moisture is adequate. Additional potential consequences of climate change in Alaska include a decrease in available water, an increase in the risk of extensive wildfires, and increased insect outbreaks.
Coastal and riverine flooding
In July 2007, this nearly century-old whaling boat was perched on an eroding bluff along the coast of the Beaufort Sea near Lonely, Alaska. Just a few months later, the boat washed away to sea in a storm.
In addition to its 6,600 miles of coast, Alaska has thousands of miles of riverbanks that are prone to flooding during extreme storms and the annual spring thaw. The shorelines and riverbanks serve as home to over 200 Alaska Native Villages, many of whose inhabitants hunt and fish for subsistence. These villages are particularly vulnerable to erosion and flooding impacts resulting from extreme storm events, especially those in areas that do not have the ability or resources to quickly respond or rebuild after disasters.
Storm-driven flooding and erosion cause millions of dollars of property damage in Alaska Native Villages, damaging or destroying homes, public buildings, and airport runways. Because these villages are often in remote areas not accessible by roads, airport runways are lifelines for their residents. Storms that cause flooding and erosion to runways can be serious threats to villages’ survival.
Move through the slides below to see how weather is becoming more extreme through the seasons in the continental U.S.
For a good summary of climate change impacts on extreme weather events, visit the National Climate Assessment:
For a great interactive on billion dollar climate disasters with maps, statistics, timelines, and more visit this NOAA site:
Risk of Extreme Weather From Climate Change to Rise Over Next Century, Report Says
By SABRINA TAVERNISEJUNE 22, 2015
Source: http://www.nytimes.com/2015/06/23/science/risk-of-extreme-weather-from-climate-change-to-rise-over-next-century-report-says.html
Drought in Puerto Rico has left the La Plata reservoir nearly empty. A study in The Lancet predicts a growing number of people will be affected by extreme weather over the next century.
Credit
Alvin Baez/Reuters
WASHINGTON — More people will be exposed to floods, droughts, heat waves and other extreme weather associated with climate change over the next century than previously thought, according to a new report in the British medical journal The Lancet.
The report, published online Monday, analyzes the health effects of recent episodes of severe weather that scientists have linked to climate change. It provides estimates of the number of people who are likely to experience the effects of climate change in coming decades, based on projections of population and demographic changes.
The report estimates that the exposure of people to extreme rainfall will more than quadruple and the exposure of people to drought will triple compared to the 1990s. In the same time span, the exposure of the older people to heat waves is expected to go up by a factor of 12, according to Peter Cox, one of the authors, who is a professor of climate-system dynamics at the University of Exeter in Britain.
Climate projections typically are expressed as averages over large areas, including vast expanses, like oceans, where people do not live. The report calculates the risk to people by overlaying areas of the highest risk for climate events with expected human population increases. It also takes into account aging populations — for example, heat waves pose a greater health risk to old people.
Men in Pakistan cool themselves in a river near Islamabad during a heatwave. The Lancet study is part of an effort to look at how climate might change life on earth for people.
Credit
Aamir Qureshi/Agence France-Presse — Getty Images
The report is part of a series of efforts to analyze how climate change might affect human health. Other major climate reports, the Intergovernmental Panel on Climate Change, a global document, and the National Climate Assessment in the United States, have addressed the issue. But Professor Cox said the new report was the first large-scale effort to quantify the effects that different types of extreme weather would have on people.
“We are saying, let’s look at climate change from the perspective of what people are going to experience, rather than as averages across the globe,” he said. “We have to move away from thinking of this as a problem in atmospheric physics. It is a problem for people.”
The Lancet first convened scientists on the topic in 2009, and produced a report that declared climate change was “the biggest global health threat of the 21st century.” Monday’s report notes that global carbon emission rates have risen above the worst-case scenarios used in 2009, and that in the absence of any major international agreement on cutting those rates, projections of mortality and illness and other effects, like famine, have worsened.
“Everything that was predicted in 2009 is already happening,” said Nick Watts, a public health expert at the Institute for Global Health at University College London, who led the team of more than 40 scientists from Europe, Africa and China that produced the report. “Now we need to take a further step forward. The science has substantially moved on.”
For years, climate change was presented in terms of natural habitats and the environment, but more recently, experts have been looking at how it might change life on earth for people. Scientists and some governments are trying to frame the dangers of climate change in health terms in order to persuade people that the topic is urgent, not simply a distant matter for scientists. Governments around the world are preparing for a United Nations summit meeting on climate change in Paris in December to discuss new policies to limit greenhouse-gas emissions.
The report measures the increase over time in “exposure events,” which it defines as the number of times people experience any given extreme weather event.
By the end of the century, the report estimates, the exposure to heat waves each year for older people around the world is expected to be around 3 billion more cases than in 1990. The number of times people of all ages are exposed to drought would increase by more than a billion a year. The rise in exposures to extreme rain would be around 2 billion a year by the end of the century, in part because populations are growing.
Even without climate change, the health problems that come along with economic development are significant, the authors note. About 1.2 million people died from illnesses related to air pollution in China in 2010, the report said.
Most broad climate reports do not go further than explaining the science, but much of the Lancet report is dedicated to policy prescriptions to slow or stop climate change and mute its effects on health. It notes that using fewer fossil fuels “is no longer primarily a technical or economic question — it is now a political one,” and urges governments to enact changes that would accomplish that.
S
Principle 8f
Oceans are becoming more acidic
The chemistry of ocean water is changed by absorption of carbon dioxide from the atmosphere. Increasing carbon dioxide levels in the atmosphere is causing ocean water to become more acidic, threatening the survival of shell-building marine species and the entire food web of which they are a part.
The oceans are not, in fact, acidic, but slightly basic. Acidity is measured using the pH scale, where 7.0 is defined as neutral, with higher levels called "basic" and lower levels called "acidic". Historical global mean seawater values are approximately 8.16 on this scale, making them slightly basic. To put this in perspective, pure water has a pH of 7.0 (neutral), whereas household bleach has a pH of 12 (highly basic) and battery acid has a pH of zero (highly acidic). Read More…
Oceans are becoming more acidic
The chemistry of ocean water is changed by absorption of carbon dioxide from the atmosphere. Increasing carbon dioxide levels in the atmosphere is causing ocean water to become more acidic, threatening the survival of shell-building marine species and the entire food web of which they are a part.
The oceans are not, in fact, acidic, but slightly basic. Acidity is measured using the pH scale, where 7.0 is defined as neutral, with higher levels called "basic" and lower levels called "acidic". Historical global mean seawater values are approximately 8.16 on this scale, making them slightly basic. To put this in perspective, pure water has a pH of 7.0 (neutral), whereas household bleach has a pH of 12 (highly basic) and battery acid has a pH of zero (highly acidic).
By the end of this century, if concentrations of CO2 continue to rise at current rates, we may expect to see changes in pH that are three times greater and 100 times faster than those experienced during the transitions from glacial to interglacial periods. Such large changes in ocean pH have probably not been experienced on the planet for the past 21 million years.
However, even a small change in pH may lead to large changes in ocean chemistry and ecosystem functioning. Over the past 300 million years, global mean ocean pH values have probably never been more than 0.6 units lower than today. Ocean ecosystems have thus evolved over time in a very stable pH environment, and it is unknown if they can adapt to such large and rapid changes. Based on the emissions scenarios of the Intergovernmental Panel on Climate Change and general circulation models, we may expect a drop in ocean pH of about 0.4 pH units by the end of this century, and a 60% decrease in the concentration of calcium carbonate, the basic building block for the shells of many marine organisms.
For a good summary of climate change impacts on ocean acidification, visit the National Climate Assessment:
Changing Ocean Temperatures and Chemistry
Source: http://nca2014.globalchange.gov/report/regions/alaska
Current and projected increases in Alaska’s ocean temperatures and changes in ocean chemistry are expected to alter the distribution and productivity of Alaska’s marine fisheries, which lead the U.S. in commercial value.
Ocean acidification, rising ocean temperatures, declining sea ice, and other environmental changes interact to affect the location and abundance of marine fish, including those that are commercially important, those used as food by other species, and those used for subsistence. These changes have allowed some near-surface fish species such as salmon to expand their ranges northward along the Alaskan coast. In addition, non-native species are invading Alaskan waters more rapidly, primarily through ships releasing ballast waters and bringing southerly species to Alaska. These species introductions could affect marine ecosystems, including the feeding relationships of fish important to commercial and subsistence fisheries.
Overall habitat extent is expected to change as well, though the degree of the range migration will depend upon the life history of particular species. For example, reductions in seasonal sea ice cover and higher surface temperatures may open up new habitat in polar regions for some important fish species, such as cod, herring, and pollock. However, continued presence of cold bottom-water temperatures on the Alaskan continental shelf could limit northward migration into the northern Bering Sea and Chukchi Sea off northwestern Alaska. In addition, warming may cause reductions in the abundance of some species, such as pollock, in their current ranges in the Bering Sea and reduce the health of juvenile sockeye salmon, potentially resulting in decreased overwinter survival. If ocean warming continues,it is unlikely that current fishing pressure on pollock can be sustained. Higher temperatures are also likely to increase the frequency of early Chinook salmon migrations, making management of the fishery by multiple user groups more challenging.
The changing temperature and chemistry of the Arctic Ocean and Bering Sea are likely changing their role in global ocean circulation and as carbon sinks for atmospheric CO2 respectively, although the importance of these changes in the global carbon budget remains unresolved. The North Pacific Ocean is particularly susceptible to ocean acidification. Acidifying changes in ocean chemistry have potentially widespread impacts on the marine food web, including commercially important species.
Ocean Acidification in Alaska
Ocean waters globally have become 30% more acidic due to absorption of large amounts of human-produced carbon dioxide (CO2) from the atmosphere. This CO2 interacts with ocean water to form carbonic acid that lowers the ocean’s pH (ocean acidification). The polar ocean is particularly prone to acidification because of low temperature, and low salt content, the latter resulting from the large freshwater input from melting sea ice and large rivers. Acidity reduces the capacity of key plankton species and shelled animals to form and maintain shells and other hard parts, and therefore alters the food available to important fish species. The rising acidity will have particularly strong societal effects on the Bering Sea on Alaska’s west coast because of its high-productivity commercial and subsistence fisheries.
Shelled pteropods, which are tiny planktonic snails near the base of the food chain, respond quickly to acidifying conditions and are an especially critical link in high-latitude food webs, as commercially important species such as pink salmon depend heavily on them for food. A 10% decrease in the population of pteropods could mean a 20% decrease in an adult pink salmon’s body weight. Pteropod consumption by juvenile pink salmon in the northern Gulf of Alaska varied 45% between 1999 and 2001, although the reason for this variation is unknown.
At some times of year, acidification has already reached a critical threshold for organisms living on Alaska’s continental shelves. Certain algae and animals that form shells (such as clams, oysters, and crab) use carbonate minerals (aragonite and calcite) that dissolve below that threshold. These organisms form a crucial component of the marine food web that sustains life in the rich waters off Alaska’s coasts. In addition, Alaska oyster farmers are now indirectly affected by ocean acidification impacts farther south because they rely on oyster spat (attached oyster larvae) from Puget Sound farmers who are now directly affected by the recent upwelling of acidic waters along the Washington and Oregon coastline.
It's Not Just Acidification that's Harming the Oceans: Two Other Major Effects of Climate Change on the Earth's Oceans
Oceans are heating up too. Learn how ocean temperatures have changed over the past century:
Climate change may be choking the ocean’s oxygen supply too. Learn about the results of an indepth study of dissolved oxygen in the Earth's oceans since 1958.
Featured Interview
Principle 8g
Ecosystems are changing
Ecosystems on land and in the ocean have been and will continue to be disturbed by climate change. Animals, plants, bacteria, and viruses will migrate to new areas with favorable climate conditions. Infectious diseases and certain species will be able to invade areas that they did not previously inhabit.
In recent years, millions of pinyon pine trees in the American Southwest have died due to drought and high heat. Global climate models predict persistent drought for the American Southwest under current rates of change. They also project changes of similar magnitude to many other ecosystems across the western US and across the globe.
Read more…
Ecosystems are changing
Ecosystems on land and in the ocean have been and will continue to be disturbed by climate change. Animals, plants, bacteria, and viruses will migrate to new areas with favorable climate conditions. Infectious diseases and certain species will be able to invade areas that they did not previously inhabit.
In recent years, millions of pinyon pine trees in the American Southwest have died due to drought and high heat. Global climate models predict persistent drought for the American Southwest under current rates of change. They also project changes of similar magnitude to many other ecosystems across the western US and across the globe.
In the Pacific Northwest (including western Montana), the current warming trend is expected to continue, with average warming of 2.1 °C (3.78 °F) by the 2040s and 3.8 °C (6.84 °F) by the 2080s; precipitation may vary slightly, but the magnitude and direction are uncertain.
This warming will have far-reaching effects on aquatic and terrestrial ecosystems in the Pacific Northwest and western Montana.
Hydrologic systems will be especially vulnerable as watersheds become increasingly rain dominated, rather than snow dominated, resulting in more autumn/winter flooding, higher peak flows, and lower summer flows. It will also greatly reduce suitable fish habitat, especially as stream temperatures increase above critical thresholds. In forest ecosystems, higher temperatures will increase stress and lower the growth and productivity of lower elevation tree species. Distribution and abundance of plant species may change over the long term, and increased disturbance (wildfire, insects, and invasive species) will cause rapid changes in ecosystem structure and function across broad landscapes. This in turn will alter habitat for a wide range of animal species by potentially reducing connectivity and late successional forest structure.
Coping with and adapting to the effects of an altered climate will become increasingly difficult after the mid-21st century, although adaptation strategies and tactics are available to ease the transition to a warmer climate. For roads and infrastructure, tactics for increasing resistance and resilience to higher peak flows include installing hardened stream crossings, stabilizing streambanks, designing culverts for projected peak flows, and upgrading bridges and increasing their height. For fisheries, tactics for increasing resilience of native trout to altered hydrology and higher stream temperature include restoring stream and floodplain complexity, reducing road density near streams, increasing forest cover to retain snow and decrease snow melt, and identifying and protecting cold-water refugia. For vegetation, tactics for increasing resilience to higher temperature and increased disturbance include accelerating development of late-successional forest conditions by reducing density and diversifying forest structure, managing for future range of variability in structure and species, including invasive species prevention strategies in all projects, and monitoring changes in tree distribution and establishment at tree line. For wildlife, tactics for increasing resilience to altered habitat include increasing diversity of age classes and restoring a patch mosaic, increasing fuel reduction treatments in dry forests, using conservation easements to maintain habitat connectivity, and removing exotic fish species to protect amphibian populations.
Learn about some of the ecosystem changes occurring in Alaska by clicking on the topics below
Ecosystems
Source: https://www.epa.gov/climate-impacts/climate-impacts-alaska#Ecosystems
Climate change is causing changes in lakes, ponds, wetlands, plant composition, and wildfires that impact human health, wildlife, and ecosystems. Lakes are changing size, with most lakes shrinking in area in the southern portion of the state. Surface waters and wetlands provide breeding habitat for millions of waterfowl and shorebirds that winter in the lower 48 states. These wetland ecosystems and wildlife resources are also important to Alaska Natives who hunt and fish for food.
Alaska highways susceptible to permafrost. Source: U.S. Arctic Research Commission (2003)
Two pairs of aerial photographs of pond areas in Alaska. The two images on the left show the pond areas in 1951 and images on the right show the same pond areas in 2000. The pond areas shown on top shrunk from 180 to 10 acres, and the pond areas shown in the bottom went from 90 to 4 acres in size. Source: USGCRP (2009)
Lakes get smaller through a combination of increased evaporation caused by warmer temperatures, permafrost thaw which allows lakes to drain more readily, and greater accumulation of decomposing plant material on lake bottoms caused by greater plant growth.
In areas where permafrost is discontinuous or fragmented across the landscape, lakes are expected to continue shrinking in area. Some lakes are growing in area because of lateral permafrost thaw, which causes the edges of the lake to collapse inward, thereby increasing the area of the lake. Lake growth is expected to continue in areas underlain with continuous permafrost.
As the climate warms, shrubs are expanding into the tundra. In some areas, shrubs are replacing lichens and other tundra vegetation. Lichens are an important winter food source for caribou, and the loss of lichens can lead to declines in the growth and abundance of these animals. Caribou, in turn, are a critical food source for predators such as bears and wolves, as well as for some Alaska Natives.
In recent years, an increase in large wildfires has been seen in Alaska. Credit: USGCRP (2014)
Higher temperatures and drier conditions increase the risks of drought, wildfire, and insect infestation. Large wildfires have consumed more boreal forest in Alaska in the last ten years than in any other decade recorded, and the area burned annually is projected to double by 2050. Fires change forest habitat, improving conditions for moose and some plant species, but reducing the lichen that caribou rely on in winter. Warmer temperatures are also expected to worsen insect damage to forests across much of the state, which may increase the area of standing dead, highly flammable trees that are especially vulnerable to wildfire.
Climate Change Could Affect Habitats in Alaska
By Dana Kobilinsky
Source: http://wildlife.org/climate-change-could-affect-habitats-in-alaska/
Posted on April 10, 2015
A caribou looks onward in Gates of the Arctic National Park and Preserve in Alaska. Researchers recently found that climate change could either increase or decrease habitat for a number of species found in Alaska such as caribou and minks.
Image Credit: Zak Richter, National Park Service
Climate change could mean an increase in some species and a decrease in others in Alaska’s Arctic and subarctic regions, according to a newly published study.
Researchers projected the effects of climate change on habitats for 162 bird species and 39 species of mammals in 62,884 square miles in Alaska, according to Bruce Marcot, a research wildlife biologist with U.S. Forest Service and the lead author of the study, which was published in the journal Climatic Change. Marcot and his coauthors from Alaska Ecoscience, National Park Service, and U.S. Geological Survey found almost 97 percent of birds and mammals in Alaska’s northwest Alaskan Arctic and subarctic regions will either gain or lose habitat as a result of climate change.
The study of wildlife in the Arctic was an “early warning about climate change for the rest of the continent,” Marcot said. As a result, making projections in this region is important.
Marcot and his coauthors set up a state-transition model to determine the influence of climate shifts on ecotypes in the area. Then, they linked wildlife habitats to an ecotype. From there, they made projections under three different outcomes: the influence of climate change in the area, various intensities and shifts of temperature, and biophysical factors such as the impact of fire and the expansion of tall shrubs and trees. Using this information, the researchers projected wildlife habitat availability by relating recent and projected vegetation changes to the habitat of the birds’ and mammals’ habitats.
Marcot and his colleagues found 52 percent of birds and mammals in the area would have habitat expansion and 45 percent would see decreases in their habitats. The remaining three percent would experience no habitat change.
Based on their research, the scientists hypothesized that woodland and forest species such as grouse and black bear will see an increase in habitat while species occupying meadow and low-shrub habitats like caribou and other small animals such as minks or muskrats will see a decrease in their habitat. They also found more mammals than birds will experience habitat declines. And, species used for hunting might also experience habitat loss, too, Marcot said. “The loss of habitat of species that are hunted for income could have very important implications for local people in the area,” he said.
Marcot said climate change might also influence soil in the region. The study predicts species such as shrews, lemmings and squirrels will suffer a habitat decline. These species help incorporate organic matter in the soil, but if their habitat is lost, that function might decline, Marcot said.
Although the study makes suggestions about the influence of climate change on Alaskan habitat, Marcot said there are, of course, unforeseen changes and ecological surprises that might unfold in the area.
“This study is a first approximation of what could happen,” Marcot said. “I hope others use this study to find out more over time and get a more accurate idea of changes to come.”
In Alaska: Too Many Fires, Not Enough Snow
The state nearly set a record for number of acres burned this year, while the Iditarod once more had to be moved north.
- ALANA SEMUELS SEP 1, 2015
WILLOW, Alaska—The strange and changing weather in the northernmost state in the union has given Bob Chlupach one hell of a year.
Chlupach’s home burned down in June during the Sockeye Fire, one of several blazes that lit up more than 5 million acres across the state of Alaska this year—making it among the worst fire seasons in the state’s history. The Sockeye Fire was man made, but scientists say that it, and others, spread faster than past fires because Alaska’s terrain is so much drier this year than usual.
That has also affected Chlupach. He and his partner Jan Steves raise and race dogs for the Iditarod, the epic sled competition across the Alaskan tundra. They were able to save their dogs from the fire, but the dry weather has wreaked havoc on the famous contest, which begins in March. For only the second time in 43 years, the race’s starting point, was moved from Willow—where the couple lives—to Fairbanks, where there was enough snow. Steves, who raced in the Iditarod in 2015 (she didn’t end up finishing the this year because her sled broke and temperatures reached 40 below), had to gather all of her gear and dogs and move them 300 miles north.
Chlupach is hesitant to blame the changes on global warming, but says he definitely notices something different in his state.
“The extremes seem to be lasting longer,” he told me, standing amid the construction of the home he is rebuilding among the charred acres near Willow. “The rain cycles, they might last a little longer, the warm weather might last a little longer.”
Statistics bear this out. The average winter temperature in Alaska has increased by six degrees over the past 60 years, and Alaska’s has had more extremely hot days and fewer extremely cold days over the last few decades, according to the National Climate Assessment. Precipitation has increased too, as winters see more rain and less snow.
Alaska Average Temperature Change by Decade
Temperature change by decade, relative to 1901-1960 average (NOAA NCDC/CICS-NC)
The nation is seeing an uptick in fires this year, as conflagrations torch acres in Washington state and California. So far, 8.1 million acres have burned across the country between January 1 and August 31 of 2015. Over the same time period last year, only 2.7 million acres burned. The majority of the country’s fires, though, occur in Alaska.
Fires have always been a part of the Alaskan landscape, as much a part of nature as spring rains or winter snows. But this winter had little snow, and the spring featured record warm temperatures, setting extremely dry conditions, said Sam Harrel, a spokesman with the U.S. Bureau of Land Management’s Alaska Fire Service. On one day near the Summer Solstice, lighting struck the state around 15,000 times, setting off dozens of fires, he said. Out of the 700-plus fires that burned in Alaska this summer, lightning caused 417.
At different points this summer, more than 200 fires were burning in Alaska at once (there’s just one currently burning).
Alaska’s fires might also be more intense than they’ve been in the past, which has worrying implications for the soil, according to Ted Schuur, a professor at Northern Arizona University who travels to the state every summer to study the soil and forest fires.
Much of Alaska is located on permafrost, once permanently-frozen soil that is beginning to thaw as temperatures rise. When that permafrost melts on the coast, it can accelerate erosion and wipe out entire swaths of land. Inland, intense fires can burn the soil that insulates that permafrost, forcing it to melt even faster. And when permafrost melts, it may release carbon into the atmosphere, Schuur said. “As things warm up, places like Alaska that have a lot of carbon stored in the soil might not always be that way. A lot of that carbon might be lost and end up back in the atmosphere, making climate change go faster.”
Normally a cold winter would help re-freeze the soil and slow the melting of permafrost, he said. But the warmer air might prevent that from happening now.
Bob Chlupach’s dogs are surrounded by burned trees. (Alana Semuels)
Of course, there are more immediate things to worry about than the melting of Alaska’s permafrost. Like how to rebuild the homes lost in the fire. I talked to a man who goes by the name “Tacoma the Fly” (because of the fishing flies he makes). He used to live in a school bus outside of Willow but it burned down in the Sockeye Fire, and he only had time to grab a change of clothes and a charger. Community members in Willow are working to build him a new house, but in the meantime, he has nowhere to live, and it’s getting colder.
“The whole world is changing,” he told me. “There’s no snow, there’s mega rains, and it’s too hot.”
The changes are disrupting people all over the state. This summer, numerous Native Alaskan villages were evacuated because of fires that threaten air quality and structures. Dozens of homes and residences burned both north and south of Anchorage. And the state, which is already broke, had to scramble to come up with the money to fight the fires.
The warmer weather and lack of snow is also proving a threat to the passion that drives most people in Willow, where many mushers live. Anchorage, 80 miles south of Willow, had the lowest snowfall on record in the 2014-2015 season, with just 25 inches falling between July 1, 2014 and June 30, 2015. Willow is now a stark landscape of charred trees and empty lots where homes once had been. One man’s whole home burned down, but the fire spared his hot tub, which he’d been trying to sell, Krista Fee, who is leading the rebuilding efforts, told me.
Many mushers are finding it much harder to participate in the race because of the lack of snow, and not just because the race didn’t begin this year in their backyard. In the 2014 race, rain wiped out much of the snow on the Iditarod trail, and one musher was knocked unconscious for an hour after hit his head on a stump in the notorious Dalzell Gorge. At the time, the trail was little different than how it appeared in summer—all gravel and rocks, he told a local TV station.
This year, it was raining in early March when the Iditarod has its ceremonial start in Anchorage, making it hazardous for the teams that had gathered there.
“It was crazy because we were so warm,” Gwenn Bogart, a musher, told me. “I just had on a raincoat.”
The beginnings of Bob Chlupach's new house (Alana Semuels)
Practicing in Willow was difficult too, Bogart said. She’s just now learning how to be a musher, and this year has had to saddle her dogs to her ATV to practice on the dirt, since the snow didn’t come. This winter, when she was practicing in the poor conditions, she flipped over a chunk of ice and was dragged under her vehicle for nearly a mile.
Bogart moved to Willow from Vermont for the snow a few years back, after she’d noticed winters in Vermont getting warmer and wetter. But so far, Alaska’s weather has been strange, too. When she went up to Fairbanks to start the race this year, there was a sudden chill and the temperature dropped to 60 below. There was snow everywhere, and Bogart decided not to race. She’d never trained on really good snow.
New mapping shows extent of yellow-cedar die-off in Alaska; analysis forecasts big losses in the future
- Author: Yereth Rosen
- Source: https://www.adn.com/alaska-news/environment/2016/11/26/new-mapping-shows-extent-of-yellow-cedar-die-off-analysis-forecasts-big-losses-in-the-future/
Now, for the first time, there are maps showing the full distribution of yellow cedars, the extent of their long-term decline and projections for future losses.
Despite its name, yellow cedar is actually a type of cypress, not cedar. Cedars and cypresses both have outstanding rot resistance, and while they have similar appearances, they're not closely related.
Yellow-cedar forest. (James Mackovjak)
The maps and calculations, described in a study published online in the journal Global Change Biology, show over 1,500 square miles of yellow cedar forest has been stricken with die-offs associated with a warming climate.
"It had never been mapped before, so we really didn't know how big the decline was," said Brian Buma of the University of Alaska Southeast, the lead author.
The future for the tree is troubled, according to the study. About half the forested area currently considered suitable for yellow cedars will no longer be so by the end of the century as temperatures rise and winter precipitation shifts from snow to rain, according to the study.
The study combines information from aerial and on-the-ground surveys in Alaska, British Columbia and points south, and it evaluated decadeslong climate trends and projections of climate change decades into the future.
Yellow cedar stands are found along the north Pacific coastline, with specimens scattered from northern California mountain sites to Prince William Sound, as the new mapping shows.
But the heart of its habitat is coastal Southeast and British Columbia — and that is where the die-off is concentrated, with mortality exceeding 70 percent in many areas. Mortality is spread over a region spanning latitude 50 to latitude 60 north, the new mapping shows.
Yellow cedars' decline of yellow-cedar is already well-documented. The long-term slide started in the mid-1800s, but accelerated in the 20th century. The past decades' die-off is attributed to warming that erases protective snow layers and exposes shallow cedar roots to freeze damage.
The trees are being considered for Endangered Species Act protections, a process spurred by a 2014 petition filed by environmental groups. If the U.S. Fish and Wildlife Service approve the listing, yellow cedar would join the Aleutian shield fern as the only Alaska plants with endangered protections.
Whether the new findings support a listing depends on how the law is interpreted, Buma said. "I don't think the results suggest that it's going to go extinct in the next few decades," he said. Still, the results show a marked and significant decline over a wide area, he said.
Like their cypress cousins in Southern bayous, yellow cedars grow in specialized conditions, using the boggy muskegs with poorly drained soils where few other trees can grow to compete for sunlight.
They thrive by spreading their fine roots in shallow areas and starting their spring growth early, even in below-freezing temperatures. Their characteristics are ideal for cool and wet Pacific Northwest areas — as long as there is snow on the ground to insulate the shallow roots.
The problem for the trees is annual snow-cover is becoming thinner and shorter-lasting. Paradoxically, the warming climate is exposing yellow cedars' roots to freeze damage.
Much of the trees that exist today "are in areas where they're not going to have snow anymore," Buma said.
But in the northern part of the range, from about Juneau to the Sound, the few yellow cedars that exist appear to be healthy, he said. There, snow is more dependable, and some trees considered young — 200 or 250 years old — have been growing.
Could yellow cedar spread farther north to stay with the snowpack? Signs do not seem encouraging.
Just as yellow cedars' death is slow, so is their growth. Seeds do not spread or sprout easily, and there is little evidence of new seedlings beyond the areas where the trees are already growing, Buma said.
Almost all the seedlings he has found have been close to existing stands, maybe no more than 10 feet away, he said. "If you go an hunt for seedlings, you barely find any outside the boundary," he said.
The coastal forest's warming, meanwhile, is on pace to beat any yellow cedar expansion, according to calculations by the University of Alaska Fairbanks' Scenarios Network for Alaska and Arctic Planning.
More winter and early-spring rain instead of snow is expected in future decades in the northern coastal forest, according to projections by the SNAP program and Chugach National Forest.
By midcentury, March will be a month with average above-freezing temperatures over wide areas of that coastal area, according to projections. Some sites, like Seward and Yakutat, are expected to pass that threshold for the month of February in coming decades.
Loss of yellow cedars could alter the forest ecosystem. The trees hold high levels of calcium, a response to the wet, low-nitrogen soils in which they grow. That calcium is put back into the forest floor from dropped foliage, affecting overall soil chemistry.
Yellow cedar may be best known for its place in Native cultures of the Pacific Northwest and Southeast Alaska.
This lovebird design box was made of yellow and red cedar by Tlingit carver Norman Jackson. It resides at the Anchorage Museum at Rasmuson Center courtesy of the Rasmuson Foundation Art Acquisition Fund. (Erik Hill / Alaska Dispatch News)
Alaska: Entering a New Era for Wildfires
Alaska, the great northern frontier of America, is being reshaped by climate change. While rising temperatures are altering its character and landscape, they are also bringing the ravages of wildfires. In the past 60 years, Alaska has warmed more than twice as fast as the rest of the country, with average temperatures up by nearly 3° F. By 2050, temperatures are projected to climb an additional 2-4 degrees, with the Arctic region seeing the most dramatic increases. These rising temperatures are expected to increase wildfire risks in Alaska, just as they have in the rest of the western U.S. Click the button below to see recent trends in Alaska wildfires.
Alaska Entering New Era for Wildfires
Source: http://www.climatecentral.org/news/alaska-entering-new-era-for-wildfires-19146
Alaska, the great northern frontier of America, is being reshaped by climate change. While rising temperatures are altering its character and landscape, they are also bringing the ravages of wildfires.
In the past 60 years, Alaska has warmed more than twice as fast as the rest of the country, with average temperatures up by nearly 3°F. By 2050, temperatures are projected to climb an additional 2-4 degrees, with the Arctic region seeing the most dramatic increases. These rising temperatures are expected to increase wildfire risks in Alaska, just as they have in the rest of the western U.S.
Wildfires have been on the rise across the western U.S. since the 1970s, at the same time that spring and summer temperatures have increased dramatically, and average spring snowpack has declined substantially.
Fires in Alaska don’t often make news in the lower 48, but they threaten vast expanses of forest, parkland, and tundra that store immense quantities of carbon. The state’s growing number of large wildfires have the potential to damage these ecosystems, and the people and wildlife that depend on them, while releasing a significant amount of carbon into the atmosphere, further contributing to global warming. Wildfire emissions over these vast areas also threaten air quality in Alaska and beyond.
Our analysis of 65 years of Alaska wildfire data shows:
- The number of large wildfires (larger than 1,000 acres) suddenly increased in the 1990s, and the 2000s saw nearly twice as many large wildfires as the 1950s and 60s.
- In the Arctic region, the number of large wildfires increased nearly tenfold in the 2000s compared to the 1950s and 60s. Only three years in the 1950s and 1960s saw large wildfires; there have been 33 large wildfires in the Arctic since 2000.
- The area burned in large wildfires each year is increasing. In just two years, 2004 and 2005, wildfires burned a larger area than in the 15 years from 1950-1964 combined. In particular, there has been a dramatic increase in wildfires larger than 10,000 acres but smaller than 50,000 acres.
- Alaska’s wildfire season is about 40 percent longer now than it was in the 1950s. The first wildfires start earlier in the year, and the last wildfires are burning longer into the fall. Overall, the wildfire season has increased more than 35 days and is now more than three months long, running from May through early August.
- Rising temperatures across Alaska have been concurrent with the rise in the number and size of Alaskan wildfires. Years with the hottest May to July temperatures also tend to be years with the most fires, and the greatest area burned.
- According to the National Climate Assessment, the amount of area burned in Alaskan wildfires is projected to double by 2050 and triple by 2100 under continued emissions and further warming.
Continental U.S.: Hotter Years, More Fires
To understand wildfire trends, Climate Central analyzed 45 years of U.S. Forest Service records of large wildfires (those fires burning more than 1,000 acres) from the western U.S. in our new report, Western Wildfires: A Fiery Future. They found that the average number of large wildfires burning each year and the total area burning in these fires have both increased dramatically since the 1970s, as you can see in the graphics below.
More fires are burning across the U.S.
More acres are burning across the U.S.
Wildfire Tracker
Hover over a red circle to see how much area has been burned. Click on it, and you’ll get more climate context and the number of people at risk. No wildfire happens in a vacuum anymore. Large wildfires — those greater than 1,000 acres — have doubled since 1970 due in part to a warming climate. And with more people living in harm’s way, that’s raising the risk of losing life and property.
For a good summaries of climate change impacts on tribes, the Northwest, and aquatic ecosystems in the Rockies, explore these publications:
Climate Impacts on Ecosystems
Source: http://www.epa.gov/climatechange/impacts-adaptation/ecosystems.html
Climate is an important environmental influence on ecosystems. Climate changes and the impacts of climate change affect ecosystems in a variety of ways. For instance, warming could force species to migrate to higher latitudes or higher elevations where temperatures are more conducive to their survival. Similarly, as sea level rises, saltwater intrusion into a freshwater system may force some key species to relocate or die, thus removing predators or prey that were critical in the existing food chain.
Climate change not only affects ecosystems and species directly, it also interacts with other human stressors such as development. Although some stressors cause only minor impacts when acting alone, their cumulative impact may lead to dramatic ecological changes. [1] For instance, climate change may exacerbate the stress that land development places on fragile coastal areas. Additionally, recently logged forested areas may become vulnerable to erosion if climate change leads to increases in heavy rain storms.
Changes in the Timing of Seasonal Life-Cycle Events
For many species, the climate where they live or spend part of the year influences key stages of their annual life cycle, such as migration, blooming, and mating. As the climate has warmed in recent decades, the timing of these events has changed in some parts of the country. Some examples are:
- Warmer springs have led to earlier nesting for 28 migratory bird species on the East Coast of the United States. [1]
- Northeastern birds that winter in the southern United States are returning north in the spring 13 days earlier than they did in the early 20th century. [4]
- In a California study, 16 out of 23 butterfly species shifted their migration timing and arrived earlier. [4]
Range Shifts
As temperatures increase, the habitat ranges of many North American species are moving northward in latitude and upward in elevation. While this means a range expansion for some species, for others it means a range reduction or a movement into less hospitable habitat or increased competition. Some species have nowhere to go because they are already at the northern or upper limit of their habitat.
For example, boreal forests are invading tundra, reducing habitat for the many unique species that depend on the tundra ecosystem, such as caribou, arctic fox, and snowy owl. Other observed changes in the United States include expanding oak-hickory forests, contracting maple-beech forests, and disappearing spruce-fir forests. As rivers and streams warm, warmwater fish are expanding into areas previously inhabited by coldwater species. [5] Coldwater fish, including many highly valued trout species, are losing their habitats. As waters warm, the area of feasible, cooler habitats to which species can migrate is reduced. [5] Range shifts disturb the current state of the ecosystem and can limit opportunities for fishing and hunting.
See the Agriculture and Food Supply Impacts & Adaptation page for information about how habitats of marine species have shifted northward as waters have warmed.
Food Web Disruptions
The Arctic food web is complex. The loss of sea ice can ultimately affect the entire food web, from algae and plankton to fish to mammals. Source: NOAA (2011)
The impact of climate change on a particular species can ripple through a food web and affect a wide range of other organisms. For example, the figure shows the complex nature of the food web for polar bears. Declines in the duration and extent of sea ice in the Arctic leads to declines in the abundance of ice algae, which thrive in nutrient-rich pockets in the ice. These algae are eaten by zooplankton, which are in turn eaten by Arctic cod, an important food source for many marine mammals, including seals. Seals are eaten by polar bears. Hence, declines in ice algae can contribute to declines in polar bear populations. [4] [5] [6]
Threshold Effects
In some cases, ecosystem change occurs rapidly and irreversibly because a threshold, or "tipping point," is passed.
One area of concern for thresholds is the Prairie Pothole Region in the north-central part of the United States. This ecosystem is a vast area of small, shallow lakes, known as "prairie potholes" or "playa lakes." These wetlands provide essential breeding habitat for most North American waterfowl species. The pothole region has experienced temporary droughts in the past. However, a permanently warmer, drier future may lead to a threshold change—a dramatic drop in the prairie potholes that host waterfowl populations and provide highly valued hunting and wildlife viewing opportunities. [3]
Similarly, when coral reefs become stressed, they expel microorganisms that live within their tissues and are essential to their health. This is known as coral bleaching. As ocean temperatures warm and the acidity of the ocean increases, bleaching and coral die-offs are likely to become more frequent. Chronically stressed coral reefs are less likely to recover.
Pathogens, Parasites, and Disease
Climate change and shifts in ecological conditions could support the spread of pathogens, parasites, and diseases, with potentially serious effects on human health, agriculture, and fisheries. For example, the oyster parasite, Perkinsus marinus, is capable of causing large oyster die-offs. This parasite has extended its range northward from Chesapeake Bay to Maine, a 310-mile expansion tied to above-average winter temperatures. [8] For more information about climate change impacts on agriculture, visit the Agriculture and Food Supply Impacts & Adaptation page. To learn more about climate change impacts on human health, visit the Health Impacts & Adaptation page.
Extinction Risks
Climate change, along with habitat destruction and pollution, is one of the important stressors that can contribute to species extinction. The IPCC estimates that 20-30% of the plant and animal species evaluated so far in climate change studies are at risk of extinction if temperatures reach levels projected to occur by the end of this century. [1] Projected rates of species extinctions are 10 times greater than recently observed global average rates and 10,000 times greater than rates observed in the distant past (as recorded in fossils). [2] Examples of species that are particularly climate sensitive and could be at risk of significant losses include animals that are adapted to mountain environments, such as the pika, animals that are dependent on sea ice habitats, such as ringed seals, and cold-water fish, such as salmon in the Pacific Northwest. [5]
For information about how communities are adapting to the impacts of climate change on ecosystems, visit the Ecosystems Adaptation section.
References
1. Fischlin, A., G.F. Midgley, J.T. Price, R. Leemans, B. Gopal, C. Turley, M.D.A. Rounsevell, O.P. Dube, J. Tarazona, A.A. Velichko (2007). Ecosystems, their Properties, Goods, and Services. In: Climate Change 2007: Impacts, Adaptation and Vulnerability . Contribution of Working Group II to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change. Parry, M.L., O.F. Canziani, J.P. Palutikof, P.J. van der Linden, and C.E. Hanson (eds.). Cambridge University Press, Cambridge, United Kingdom.
2. Millennium Ecosystem Assessment (2005). Ecosystems and Human Well-Being: Biodiversity Synthesis (PDF). World Resources Institute, Washington, DC, USA.
3. CCSP (2009). Thresholds of Climate Change in Ecosystems . A report by the U.S. Climate Change Science Program and the Subcommittee on Global Change Research. Fagre, D.B., Charles, C.W., Allen, C.D., Birkeland, C., Chapin, F.S. III, Groffman, P.M., Guntenspergen, G.R., Knapp, A.K., McGuire, A.D., Mulholland, P.J., Peters, D.P.C., Roby, D.D., and Sugihara, G. U.S. Geological Survey, Department of the Interior, Washington DC, USA.
4. CCSP (2008). The Effects of Climate Change on Agriculture, Land Resources, Water Resources, and Biodiversity in the United States . A Report by the U.S. Climate Change Science Program and the Subcommittee on Global Change Research. Backlund, P., A. Janetos, D. Schimel, J. Hatfield, K. Boote, P. Fay, L. Hahn, C. Izaurralde, B.A. Kimball, T. Mader, J. Morgan, D. Ort, W. Polley, A. Thomson, D. Wolfe, M. Ryan, S. Archer, R. Birdsey, C. Dahm, L. Heath, J. Hicke, D. Hollinger, T. Huxman, G. Okin, R. Oren, J. Randerson, W. Schlesinger, D. Lettenmaier, D. Major, L. Poff, S. Running, L. Hansen, D. Inouye, B.P. Kelly, L Meyerson, B. Peterson, and R. Shaw. U.S. Environmental Protection Agency, Washington, DC, USA.
5. USGCRP (2009). Global Climate Change Impacts in the United States . Karl, T.R., J.M. Melillo, and T.C. Peterson (eds.). United States Global Change Research Program. Cambridge University Press, New York, NY, USA.
6. ACIA (2004). Impacts of a Warming Arctic: Arctic Climate Impact Assessment . Arctic Climate Impact Assessment. Cambridge University Press, Cambridge, United Kingdom.
7. NRC (2008). Understanding and Responding to Climate Change: Highlights of National Academies Reports . National Research Council. The National Academies Press, Washington, DC, USA.
8. NRC (2008). Ecological Impacts of Climate Change . National Research Council. The National Academy Press, Washington, DC, USA.
S
The Rapid and Startling Decline
Of World’s Vast Boreal Forests
Source: http://e360.yale.edu/feature/the_rapid_and_startling_decline_of_worlds_vast_boreal_forests/2919/
Scientists are becoming increasingly concerned about the fate of the huge boreal forest that spans from Scandinavia to northern Canada. Unprecedented warming in the region is jeopardizing the future of a critical ecosystem that makes up nearly a third of the earth’s forest cover.
by jim robbins
The boreal forest wraps around the globe at the top of the Northern Hemisphere in North America and Eurasia. Also known as taiga or snow forest, this landscape is characterized by its long, cold and snowy winters. In North America it extends from the Arctic Circle of northern Canada and Alaska down into the very northern tip of the United States in Idaho, Washington, Montana, and Minnesota. It's the planet's single largest biome and makes up 30 percent of the globe's forest cover.
Moose are the largest ungulate in the boreal, adapted with their long legs to wade in its abundant marshes, lakes and rivers eating willows, aspen and other plants. In the southern boreal forest of northern Minnesota, moose were once plentiful, but their population has plummeted. Thirty years ago, in the northwest part of the state, there were some 4,000; they now number about a hundred. In the northeast part, they have dropped from almost 9,000 to 4,300. They’ve fallen so far, so fast that some groups want them listed as endangered in the Midwest.
Hare and Ritchie, 1972
The boreal forest extends around the earth at the top of the Northern Hemisphere.
Moose carcasses deteriorate rapidly before they are found, and so forensics has not been able to determine why they are dying. Some experts surmise it could be that tens of thousands of ticks that mob an animal and weaken it. Others think it's a parasite called liver flukes, or the fact that winters have gotten so warm the animals can't regulate their body temperature and die from heat stress.
But Dennis Murray, a professor of ecology at Trent University in Peterborough, Ontario, thinks the dying moose of Minnesota and New Hampshire and elsewhere are one symptom of something far bigger – a giant forest ecosystem that is rapidly shrinking, dying, and otherwise changing. "The boreal forest is breaking apart," he says. "The question is what will replace it?"
Many scientists, in fact, are deeply concerned about the state of the world’s largest forest. The Arctic and the boreal region are warming twice as fast as other parts of the world. Permafrost is thawing and even burning, fires are burning unprecedented acres of forest, and insect outbreaks have gobbled up increasing numbers of trees. Climate zones are moving north ten times faster than forests can migrate. And this comes on top of increased industrial development of the boreal, from logging to oil and gas. The same phenomena are seen in Russia, Scandanavia, and Finland.
These disturbing signals of a forest in steep decline are why NASA just launched a large-scale research project called ABoVE — Arctic Boreal Vulnerability Experiment, a “major field campaign” with 21 field projects
over the next decade. But the studies will confirm in detail what many know is well underway.
“Boreal forests have a potential to hit a tipping point this century,” said Anatoly Shvidenko, of the International Institute for Applied Systems Analysis and a co-author of a survey of a recent research on boreal forests in the journal Science. “It is urgent we place more focus on climate mitigation and adaptation with respect to these forests.”
A tipping point would include the mother of all concerns: the unbridled melting of permafrost, one of the main thrusts of the ABoVE project. The permafrost in the boreal is more susceptible to thawing than in the Arctic because it’s closer to the freezing point. If large-scale melting occurs it would release more carbon dioxide and methane, which have been bound up in the frozen soil for thousands of years, and bring on more warming, and then more thawing, a dangerous loop. “Scientists call it a positive feedback, but most people call that a vicious cycle,” said Peter Griffith, chief support scientist for the ABoVE project.
Murray has been researching the boreal forest for 25 years, and he and his colleagues have seen many changes firsthand. In British Columbia, 80 percent of the province's mature lodgepole, another boreal species, have recently died from the mountain pine beetle, whose range and season both expanded greatly because of a warmer world. White and black spruce, the main trees species in the boreal, are also dying in vast numbers “The southwest Yukon looks dramatically different than it did 25 years ago when I did my master’s [degree],” he said. “Everywhere you go there is deadfall.”
NOAA
White spruce, shown above near the Denali Highway in Alaska, have been dying off in the boreal forest.
NASA has also seen a lot of forest browning in its studies, large swaths of forests with reduced growth that turn brown in the hotter than normal summers, and which contribute to much bigger and hotter fires and the thawing of the permafrost. “Severe fires burn a foot or more of organic soil and that's the insulating layer that keeps the permafrost frozen,” said Scott Goetz, lead scientist on the ABoVE project. “Once that is removed the thaw is much more rapid.”
The fires also change the vegetation. “When you remove that organic soil you get deciduous re-growth that lasts for decades,” said Goetz. “Maybe it will never come back as coniferous.”
Typically, when black spruce dies, it is replaced with new black spruce. “That’s been going on for a long, long time, [but] not anymore,” Murray says. “You lose spruce and you lose everything that lives in spruce and that is basically everything in the boreal forest. We’re seeing the same phenomena that we’ve seen with moose with lynx and snowshoe hares. And caribou are going belly up very, very fast. Their ranges are receding northward rapidly.”
The boreal is also home to some 5 billion birds. Many species have shifted their ranges north. “Climate change is having an impact much more quickly than we thought,” said Jeff Wells, a senior scientist with the International Boreal Campaign who focuses on birds. “Shifts that researchers thought would take place over 50 or a hundred years have taken place over a decade.”
But the changes in such a large system are complex. The forest isn’t merely receding north, it’s dying in some places in its interior and surviving quite well in others. A 2015 study found that while boreal spruce forest in interior Alaska is dying out because of warm temperatures, the same forest on the state’s west coast is thriving.
The dying spruce and moose and lynx and other changes are the dots that scientists are trying to connect to get a sense of what the boreal forest in North America will look like in the next half century.
The caveat is that in a system this massive and complex there are so many variables it's difficult to forecast with much certainty. The projected changes, for example, are based on the Intergovernmental Panel on Climate Change's temperature forecast of a rise of some 10 degrees by 2100. Should things warm faster or go higher, the changes could come faster and be deeper or different than modeled. And many changes could simply be unpredictable.
Murray’s modeling shows that a large gap is opening in the boreal in Ontario and Quebec, a gap some 500 by 350 kilometers. It will essentially split the contiguous forest into two separate forests — one to the east, the other to the west — as the black spruce and white spruce disappear. That gap could then become grassland or Carolinian, the forest ecosystem that dominates south of the boreal in Ontario, characterized by oak, maple, black walnut and other deciduous species.
As the spruce goes, so goes its inhabitants. "We're predicting there’s going to be no lynx, moose, or hare in central Ontario in the years to come,” Murray says, “so we’re going to have disjunct populations on either side." It could cause a break between populations of species and a loss of genetic diversity.
Murray has coined a term for the patchy quality of the effects of warming on the boreal – climate fragmentation. “Because it’s a gradual transition, it won’t be real boreal and it won’t be real deciduous,” says Murray. “Ecosystems will likely be less stable and more open to invasives.”
Changes in snow cover are already driving changes. In some places snow covers the ground for shorter periods, and the conditions of the snow are also changing. Instead of three feet of fluffy snow all winter, temperatures rise and melt the snow and then get cold and freeze it and compact it into ice, again and again. In such conditions, lynx, which have thick, padded paws that serve as de facto snowshoes and allow them to hunt atop deep snow, loses it evolutionary advantage. “It affects their ability to survive,” says Murray. “Coyotes, on the other hand, are extremely plastic and flexible. They weren't in the boreal a hundred years ago, but they are there now. They aren't everywhere, because they don’t do well in deep snow, but that's changing.” They are competing with lynx by foraging for their kills and preying on hares and squirrels.
The die-off of much of the boreal forest could have serious and unpredictable repercussions on the global climate system. When British Columbia’s lodgepole forests died, the province went from being a carbon sink to a carbon source because the dead forests released massive amounts of stored CO2. If the spruce forests of the boreal disappear they could also alter climate systems by releasing CO2. Because they are dark, they also absorb heat, but a treeless, snow-covered landscape would reflect far more solar energy back into the atmosphere.
Knowing what could happen in the next 50 or 60 years, and where, is important for conservation and other strategies. The boreal, especially in Canada, isn’t just a forest. It’s woven into the fabric of the region’s life and culture. Hundreds of First Nations call the boreal home, and they depend on it for sustenance, hunting moose and caribou, picking berries, and fishing. Paper and lumber industries also depend on a healthy boreal.
The research NASA is doing will be used to help determine how communities and land managers in the boreal might adapt to changes. Dall sheep in the Yukon, for example, are in decline and a subject of one of NASA's studies. The results will be given to provincial and federal officials in Canada to make decisions on issues ranging from hunting to access to land management.
Meanwhile, in the hope of slowing the thawing of boreal permafrost, the International Boreal Conservation Campaign has launched a “cold carbon storage campaign.” This initiative is aimed at managing the boreal in ways that keep as much as possible frozen — no road building atop it, for example, or the creation of new large scale carbon reserves.
But such measures can only do so much. The real decisions on the fate of the boreal are up to the world community. It’s not a good sign that when I contacted Canadian Forest Service scientist Sylvie Gauthier, the lead author of the Science paper that surveyed threats to the boreal, I was told by a public affairs officer that the interview would be on “deep background only” with no attribution to her or her employer. The federal government of Canada, facing some the world’s most serious climate change threats, has gone to great lengths to squelch any discussion of this issue.
Yet even as they redouble their research efforts, scientists know the ultimate answer is not about adaptation or more research, but a rapid reduction in global CO2 emissions, which so far has shown little hope of being achieved. NASA’s Griffith says the situation reminds him of his father, a small-town doctor. “Even when the patient ignored his advice over and over again, he would continue to treat the patient,” he said. “A lot of us in the climate and ecosystem world are finding ourselves dealing with a similar kind of problem.”
POSTED ON 12 OCT 2015
S
Marine food chains at risk of collapse, extensive study of world's oceans finds
Source: http://www.theguardian.com/environment/2015/oct/13/marine-food-chains-at-risk-of-collapse-extensive-study-of-worlds-oceans-reveals
The food chains of the world’s oceans are at risk of collapse due to the release of greenhouse gases, overfishing and localised pollution, a stark new analysis shows.
A study of 632 published experiments of the world’s oceans, from tropical to arctic waters, spanning coral reefs and the open seas, found that climate change is whittling away the diversity and abundance of marine species.
The paper, published in the Proceedings of the National Academy of Sciences, found there was “limited scope” for animals to deal with warming waters and acidification, with very few species escaping the negative impact of increasing carbon dioxide dissolution in the oceans.
The world’s oceans absorb about a third of all the carbon dioxide emitted by the burning of fossil fuels. The ocean has warmed by about 1C since pre-industrial times, and the water increased to be 30% more acidic.
The acidification of the ocean, where the pH of water drops as it absorbs carbon dioxide, will make it hard for creatures such as coral, oysters and mussels to form the shells and structures that sustain them. Meanwhile, warming waters are changing the behaviour and habitat range of fish.
The overarching analysis of these changes, led by the University of Adelaide, found that the amount of plankton will increase with warming water but this abundance of food will not translate to improved results higher up the food chain.
“There is more food for small herbivores, such as fish, sea snails and shrimps, but because the warming has driven up metabolism rates the growth rate of these animals is decreasing,” said associate professor Ivan Nagelkerken of Adelaide University. “As there is less prey available, that means fewer opportunities for carnivores. There’s a cascading effect up the food chain.
“Overall, we found there’s a decrease in species diversity and abundance irrespective of what ecosystem we are looking at. These are broad scale impacts, made worse when you combine the effect of warming with acidification.
“We are seeing an increase in hypoxia, which decreases the oxygen content in water, and also added stressors such as overfishing and direct pollution. These added pressures are taking away the opportunity for species to adapt to climate change.”
The research adds to recent warnings over the state of the oceans, with the world experiencing the third global bleaching of coral reefs.
Since 2014, a massive underwater heatwave, driven by climate change, has caused corals to lose their brilliance and die in every ocean. By the end of this year 38% of the world’s reefs will have been affected. About 5% will have died.
Coral reefs make up just 0.1% of the ocean’s floor but nurture 25% of the world’s marine species. There are concerns that ecosystems such as Australia’s Great Barrier Reef, which has lost half its coral cover over the past 30 years, could be massively diminished by 2050 unless greenhouse gas emissions are slashed and localised pollution is curbed.
Meanwhile, warming of the oceans is causing water to thermally expand, fuelling sea level rises caused by melting land ice. Research released in the US on Monday found that Antarctic ice is melting so fast that the whole continent could be at risk by 2100, with severe consequences for coastal communities.
Problems in the ocean’s food chains will be a direct concern for hundreds of millions of people who rely upon seafood for sustenance, medicines and income. The loss of coral reefs could also worsen coastal erosion due to their role in protecting shorelines from storms and cyclones.
“These effects are happening now and will only be exacerbated in the next 50 to 100 years,” Nagelkerken said. “We are already seeing strange things such as the invasion of tropical species into temperate waters off south-eastern Australia. But if we reduce additional stressors such as overfishing and pollution, we can give species a better chance to adapt to climate change.”
S
US forests struggle as drought and climate change bite
The speed at which the climate is changing is outstripping forests’ ability to adapt to drier, hotter conditions across vast swathes of the US and Canada
Yosemite national park in California is one of many in the region afflicted by drought – water levels in the Merced River are up to 4 feet lower than usual (Pic: Pixabay)
By Tim Radford
Drought and climate change are now threatening almost all the forests of the continental US, according to new research.
Scientists from 14 laboratories and institutions warn in the journal Global Change Biology that climate is changing faster than tree populations can adapt
Existing forests, effectively and literally rooted to the spot, are experiencing conditions hotter and less reliably rainy than those in which they had evolved.
“Over the last two decades, warming temperatures and variable precipitation have increased the severity of forest droughts across much of the continental United States,” says James Clark, professor of global environmental change at Duke University, North Carolina.
He and colleagues synthesised hundreds of studies to arrive at a snapshot of changing conditions and a prediction of troubles ahead.
Ominous predictions
Other research has already delivered ominous predictions for the forests of the US southwest, but the scientists warn that other, normally leafier parts of the continent face increasing stress. Dieback, bark beetle infestation and wildfire risk may no longer be confined to the western uplands.
“While eastern forests have not experienced the types of changes seen in western forests in recent decades, they too are vulnerable to drought and could experience significant changes with increased severity, frequency, or duration in drought,” the authors say.
Professor Clark puts it more bluntly: “Our analysis shows virtually all US forests are now experiencing change and are vulnerable to future declines.
Given the uncertainty in our understanding of how forest species and stands adapt to rapid change, it’s going to be difficult to anticipate the type of forests that will be here in 20 to 40 years.”
Quite what happens depends on the speed at which nations switch from fossil fuels – which release the greenhouse gases that drive global warming – to renewable energy. But because carbon dioxide levels in the atmosphere have risen sharply in the last century, some degree of change is inevitable.
“This is like climate change on steroids, and it happens over much more rapid timescales”
A team of researchers from the University of Colorado Boulder took a closer look at how hotter and drier conditions affect forests. They report in Ecology Letters that felling and forest clearance seem to make things worse, as the newly-exposed edges of an existing forest become more susceptible to drastic temperature changes.
“When you chop down trees, you create hotspots in the landscape that are just scorched by the sun. These hotspots can change the way that heat moves through a landscape,” says the report’s lead author, Kika Tuff, a PhD student at the university’s department of ecology and evolutionary biology.
Low air pressure in the cleared spots pulls the cool moist air from the shade of the trees, to be replaced by hot, dry air. The cleared areas then get the rainfall, while the nearby forest dries.
The warming effect is most pronounced within between 20 and 100 metres of the forest’s edge, where temperatures can be as much as 8°C higher than deep in the forest interior.
Since 20% of the world’s remaining forests lie within 100 metres of an edge, and more than 70% lie within a kilometre of an edge, the discovery suggests that thewarming effect could be happening anywhere, or everywhere.
Tuff says: “This is like climate change on steroids, and it happens over much more rapid timescales.”
Millennium of growth
Meanwhile, to look more closely at the stresses that forests are now facing, two researchers at Washington State University in Vancouver report in the Royal Society Open Science journal that they have made a mathematical model of a forest, enabling them to replicate a millennium of growth and change in about three weeks.
They say they have already used the model to predict increasing fire rates in the hardwood forests of Quebec, because of rising carbon dioxide levels and warmer temperatures.
The model is based on data collected by drone surveys, and it is, they say, the only simulation that creates intricate root systems and canopy structures for each tree. The idea is to provide a tool that can help foresters plan for change.
“One of the major concerns is how climatic changes, in particular droughts, can affect forest structure and dynamics,” they write.
“Drive an hour east along the Columbia River from Vancouver and you will notice a complete transition from very dense forests to savanna and then to desert,” says Nikolay Strigul, assistant professor of mathematics and statistics at Washington State.
“The fear is that drier conditions in the future will prevent forests in places like Washington from re-establishing themselves after a clear-cut or wildfire. This could lead to increasing amounts of once-forested areas converted to desert.”
This article was produced by the Climate News Network
S
Principle 8h
Climate change is altering the timing of natural events
Timing matters: Flowers bloom, insects emerge, birds migrate, and planting and hunting seasons are carefully coordinated times in order to take advantage of what other organisms, or the weather, is up to.
But increasing research is showing some of these relationships are falling out of sync as climate change alters important cues, such as the arrival of spring warmth.
"There are going to be winners and losers," said David Inouye, a biology professor at the University of Maryland, Read more…
Climate change is altering the timing of natural events
Timing matters: Flowers bloom, insects emerge, birds migrate, and planting and hunting seasons are carefully coordinated times in order to take advantage of what other organisms, or the weather, is up to.
But increasing research is showing some of these relationships are falling out of sync as climate change alters important cues, such as the arrival of spring warmth.
"There are going to be winners and losers," said David Inouye, a biology professor at the University of Maryland, who has followed seasonal events at the Rocky Mountain Biological Laboratory in Colorado since 1973. "The ultimate outcome will be that some species go extinct and some manage to adapt."
This isn't just a problem for the natural world. Shifts in seasonal events can have direct implications for humans, "because we, as human societies, are adapted to certain seasonal conditions," said Shannon McNeeley, a postdoctoral researcher at the National Center for Atmospheric Research (NCAR) who has studied how a mismatch is playing out in Alaska. There, changes in the moose migrations have made it difficult for native people to obtain the meat they need during the legal hunting season.
Source: http://www.livescience.com/19679-climate-change-seasons-shift-mismatch.html
Featured Interview
For a good summary of impacts on seasonal patterns of plants and animals, visit the National Climate Assessment:
For a brief account of how climate change is affecting hummingbirds and their nectar sources, read this article from Audubon:
Are Early Blooms Putting Hummingbirds At Risk?
Audubon’s chief scientist talks migration, climate change, and what you can do to help.
Jesse Greenspan
Published Apr 07, 2015
No one understands the relationship between climate change and hummingbirds better than Audubon’s chief scientist Gary Langham. He led a groundbreaking study in 2014 that determined that about half of all North American bird species will lose their homes if we don’t do something to stop global warming. Now, to further that study, Audubon is sourcing data from people across the country who host hummingbirds in their backyards. The project, called Hummingbirds at Home, starts up again on April 8.
Langham emphasized the importance of Hummingbirds at Home to Audubon while answering questions about what will happen to the 18 or so hummingbird species in the United States (including rare visitors from Mexico) and the role citizen scientists play in ensuring their survival.
What were some of the regular challenges of a hummingbird migration even before climate change became a factor?
Well, any kind of migration, let alone a hummingbird, is sort of a minor miracle. Imagine a Ruby-throated Hummingbird crossing the Gulf of Mexico in one flight. How in the world does it have enough energy stored up in that little body? It’s just amazing. And then you factor in all of the threats it has to encounter, from weather to manmade structures.
So how has climate change made it worse?
If the nectar sources you depend on bloom too early, you run the risk of showing up after the party’s already over. That’s one of the things that got us thinking about Hummingbirds at Home. The Broad-tailed Hummingbird’s primary food source right now is this big yellow flower called the glacier lily. There’s research out of the University of Maryland showing that the bird is still arriving at its breeding grounds in the Rockies at the same time as previous years, but that climate change is causing the glacier lily to open up earlier and earlier in the season. It’s not hard to extrapolate that soon, Broad-tailed Hummingbirds may show up and not have their main food source. Maybe new flowers will take the glacier lily’s place. Or maybe this shift will turn out to be really bad for the bird.
Are some hummingbirds more endangered by climate change than others?
The hummingbird I grew up with in California, the Anna’s Hummingbird, was mercifully on the climate stable list (in the Audubon Birds and Climate Change Report). But unfortunately, one of the other coastal California hummingbirds, the Allen’s, is listed as climate-endangered. Its summer range seems to be decreasing, whereas the winter range is shifting northward pretty dramatically. The Rufous is also listed as climate-endangered. In some ways, it might be affected even more dramatically than the Allen’s. The other two species listed as climate-threatened are the Calliope and Black-chinned Hummingbirds.
So the Broad-tailed isn’t one of them?
While the Broad-tailed Hummingbird, in the way we did the climate report, was shown to be stable, its food sources are not. The food sources and a lot of ancillary things that are really important to animals are actually not included in our report. And that makes the prospects even more dire than what we projected.
How will Hummingbirds at Home help these species?
If we can better understand what the hummingbirds are feeding on, we can maybe get ahead of the curb and plant things that are either climate-stable or that will properly match up with the birds’ migrations. To me, the next iteration is to generate a specific list of plants that people can use for hummingbirds in their areas.
In the three years since Hummingbirds at Home started, what has stood out to you about the project?
People are very passionate about their backyards and gardens, and they’re very passionate about hummingbirds. Hummingbirds are like raptors. They somehow have this supernatural ability to capture people’s attention. Because hummingbirds come in people’s yards, they’re also a great way to engage kids. One of the things that’s kind of lost in our digital world is that connection to nature.
Is the eventual goal to have something as long-running and as scientifically useful as, say, the Breeding Bird Survey or the Christmas Bird Count?
I think that would be great! I hesitate to forecast anything for an individual project, but I could imagine that it would do just that. Or maybe we’ll broaden it to be more inclusive of a broader range of birds, or maybe it will be absorbed by something else. We want whatever it is we’re doing to feel meaningful to people and be fun and free and family-friendly.
S
Climate Impacts on Wildlife
Jessica Aldred
Monday 31 March 2014 07.31 EDT
Source: http://www.theguardian.com/environment/2014/mar/31/ipcc-climate-report-wildlife-impact
Polar bears are seen south of Churchill, Manitoba, in this undated handout photo. Lightning-sparked wildfires along Canada's Hudson Bay are threatening polar bears' summer habitat, encroaching on the old tree roots and frozen soil where females make their dens, an conservation expert on the big white bears said on Thursday. Photograph: Reuters
One focus of the latest report from the UN panel on climate change is the impact on Earth's ecosystems. The report from the Intergovernmental Panel on Climate Change (IPCC) says that in recent decades, many plant and animal species have moved their range, changed numbers or shifted their seasonal activities as a result of warmer temperatures.
Moving on up
Species are matching temperature rises by increasingly shifting their range (the geographic area to which their activity is confined) towards the cooler poles or higher altitudes – sometimes three times faster than previously thought. Species that already inhabit the upper limit of their habitat – such as the polar bear, snow leopard or dotterel – literally have nowhere left to go.
The British comma butterfly has moved 137 miles northward in the past two decades, while geometrid moths on Mount Kinabalu in Borneo have shifted uphill by 59 metres in 42 years. The quiver tree of southern Africa is increasing as it moves towards the south pole, but dying of heat and water stress in its shrinking northern range. Dartford warblers have been steadily moving northwards in the UK while declining on the southern edge of their range in Spain.
A comma butterfly in Kent, UK. Photograph: Robert Pickett/Alamy
In the seas, rising numbers of warm-water crustaceans have been found around Norway's polar islands, while the snow crab has extended its range northwards by up to 311 miles. The IPCC report warns that many species will be unable to move fast enough to track suitable climates, with plants, amphibians and small mammals in flat landscapes or that remain close to their breeding site particularly vulnerable.
Seasonal shift
For many species, climate influences important stages in their annual life cycle, like migration or mating. The report shows major shifts in this "phenology" in recent decades, mainly in the northern hemisphere. "Spring advancement" – the earlier occurrence of breeding, bud burst, breaking hibernation, flowering and migration – has been found in hundreds of plant and animal species in many regions. Migratory birds including the whitethroat, reed warbler and song thrush are arriving earlier, three species of Japanese amphibians have been found to be breeding earlier, while the edible dormouse has been emerging earlier from hibernation by an average of eight days per decade.
Climate change is disrupting flower pollination, research shows
Damian Carrington
Thursday 6 November 2014 12.00 EST
Source: http://www.theguardian.com/environment/2014/nov/06/climate-change-is-disrupting-flower-pollination-research-shows
New research reveals that rising temperatures are causing bees to fly before flowers have bloomed, making pollination less likely
The early spider orchid and miner bee, that depend on each other for reproduction, have become increasingly out of sync as spring temperatures rise, research has shown. Photograph: Friedhelm Adam/Getty Images
Sexual deceit, pressed flowers and Victorian bee collectors are combined in new scientific research which demonstrates for the first time that climate change threatens flower pollination, which underpins much of the world’s food production.
The work used museum records stretching back to 1848 to show that the early spider orchid and the miner bee on which it depends for reproduction have become increasingly out of sync as spring temperatures rise due to global warming.
The orchid resembles a female miner bee and exudes the same sex pheromone to seduce the male bee into “pseudocopulation” with the flower, an act which also achieves pollination. The orchids have evolved to flower at the same time as the bee emerges.
But while rising temperatures cause both the orchid and the bee to flower or fly earlier in the spring, the bees are affected much more, which leads to a mismatch.
“We have shown that plants and their pollinators show different responses to climate change and that warming will widen the timeline between bees and flowers emerging,” said Dr Karen Robbirt, at the Royal Botanic Gardens, Kew and the University of East Anglia (UEA). “If replicated in less specific systems, this could have severe implications for crop productivity.”
She said the research, published in Current Biology on Thursday, is “the first clear example, supported by long-term data, of the potential for climate change to disrupt critical [pollination] relationships between species.”
Three-quarters of all food crops rely on pollination, and bees and other pollinators have already suffered heavily in recent decades from disease, pesticide use and the widespread loss of the flowery habitats on which they feed. In the UK alone, the free fertilisation provided by pollinators is estimated to be worth £430m a year to farmers.
Professor Anthony Davy, also at UEA and part of the research team, said: “There will be progressive disruption of pollination systems with climatic warming, which could lead to the breakdown of co-evolved interactions between species.”
Scientists have already identified a few timing mismatches caused by global warming between species and their prey. Oak tree buds are eaten by winter moths, whose caterpillars are in turn fed by great tits to their chicks, but the synchronicity of all these events has been disrupted.
Suspected mismatches have occurred between sea birds and fish, such as puffins and herring and guillemots and sand eels. The red admiral butterfly and the stinging nettle, one of its host plants, are also getting out of sync.
The new study focused on the early spider orchid Ophrys sphegodes, found in southern England, and the solitary miner bee species Andrena nigroaenea because they have a very close relationship. Other plants can be pollinated by many insects and other insects can pollinate many plants, making it very hard to determine the effect of changing temperatures.
The solitary miner bee is affected more by rising temperatures than the early spider orchid that it pollinates. Photograph: Oxford University
Another challenge is that the temperature effects can be subtle, meaning data has to be collected over a long period. Robbirt and her colleagues realised that the natural history museums in London and Oxford and Kew Gardens had dated specimens of both the orchid and the bee stretching back to 1848.
Analysing all the data, and checking it against recent surveys, revealed that the orchid flowers six days earlier for every 1C increase in spring temperatures. But the effect on the male miner bee was greater, as it emerged nine days earlier.
The female miner bees, which usually emerge later than the male, emerged 15 days earlier. The latter effect meant the male bees were less likely to visit the orchid flowers for pseudocopulation. “The orchids are likely to be outcompeted by the real thing,” said Robbirt.
The UK government published its national pollinator strategy on Tuesday. It was welcomed by the pesticide trade body, the Crop Protection Association and the National Farmers Union. But Joan Walley MP, chair of parliament’s Environmental Audit Committee, said: “I am disappointed the government seems stubbornly determined to keep open the possibility of challenging the EU ban on neonicotinoid pesticides, which have been linked to pollinator declines.”
S
Climate Change Throws Nature's Timing Out of Whack
by Wynne Parry 
Timing matters: Flowers bloom, insects emerge, birds migrate, and planting and hunting seasons are carefully coordinated times in order to take advantage of what other organisms, or the weather, is up to.
But increasing research is showing some of these relationships are falling out of sync as climate change alters important cues, such as the arrival of spring warmth.
"There are going to be winners and losers," said David Inouye, a biology professor at the University of Maryland, who has followed seasonal events at the Rocky Mountain Biological Laboratory in Colorado since 1973. "The ultimate outcome will be that some species go extinct and some manage to adapt."
This isn't just a problem for the natural world. Shifts in seasonal events can have direct implications for humans, "because we, as human societies, are adapted to certain seasonal conditions," said Shannon McNeeley, a postdoctoral researcher at the National Center for Atmospheric Research (NCAR) who has studied how a mismatch is playing out in Alaska. There, changes in the moose migrations have made it difficult for native people to obtain the meat they need during the legal hunting season.
"This more subtle seasonal change has not been a main focus of climate research," McNeeley said. "I think it is going to be one that emerges more and more as we see these changes happening, and we start to have more conflicts around this."
Changes in nature
Evidence going back decades and sometimes even longer shows the timing of some biological events is shifting around the world. Studies document the progressively earlier arrival of spring, by about 2.3 to 5.2 days per decade in the last 30 years, according to the Intergovernmental Panel on Climate Change's 2007 report. That report lists studies showing changes in seasonal timing, or phenology, of the first and last leaves on gingko trees in Japan, butterfly emergence in the United Kingdom, bird migrations in Australia, the first leaves and flowers of lilacs in North America, among many others.
But not everything is changing together, leading to complex results.
During his years in the Colorado mountains, Inouye has seen the winter snow melt earlier, the result of warmer springs, less snowfall during the winter and more dust carried in by storms, which accelerates melting. The last frost, however, continues to happen at about the same time.
His work indicates this is bad for the Mormon fritillary butterfly since an early start to the growing season may put caterpillars and the flower buds that could later feed adult butterflies at the mercy of frosts. Migratory hummingbirds, which also consume the flowers' nectar, are arriving earlier in the spring now, but they aren't quite keeping pace with the first flowers, a potential mismatch that could ultimately lead to fewer flowers for the birds to pollinate, said Inouye.
Decades of data show that robins are showing up earlier, as are the hibernating marmots, and there is evidence that this shift is benefiting the marmots, who appear to be putting on more weight during the summer.
Records of spring flowers in Concord, Mass., initially kept by Henry David Thoreau, show that not only are flowers blooming earlier, the species that haven't moved up their first bloom dates are disappearing.
Human implications
Even in modern society, human activities track the seasons. In search of shifts in human phenology, one study looked at national park attendance, and found a shift toward peak attendance earlier in the year for parks located in places where spring is getting warmer.
The effects of climate change are showing up dramatically in the Arctic, and changes in the timing of seasonal events are no exception, McNeeley said. "You are starting to see these seasonality mismatches in a much more enhanced way than you are in the lower 48 [U.S. states]," she said.
These changes are pushing nature and human regulatory systems apart, creating problems for Alaskan natives who depend on wild food, particularly moose, but can only legally hunt it during a specific period. The hunting season, historically, has been timed to the moose migration out of their summer feeding grounds into the territory where they perform their annual mating ritual. But lately the moose have been staying at their feeding grounds until later into the season.
"People haven't had time to harvest moose for winter and then the hunting season shuts down," McNeeley said. "That gives them two choices, either they go without moose … or they have to hunt illegally, which comes with huge penalties if they get caught."
Over the past decade, tribes have sought to shift the hunting season, but their efforts have been almost completely unsuccessful, due largely to biologists' concerns about the effects on the breeding season, she said.
In the lower 48 states, earlier snowmelt and a longer growing season are likely to create conflicts related to water rights, but updating policies will likely be difficult. The fundamental problem is the scarcity of the resource, Douglas Kenney, director of the Western Water Policy Program at the University of Colorado, told AtmosNews, an online publication of NCAR.
"This particular issue of the timing of seasons and phenology and the legal system is something that has been really understudied and I think needs to receive a lot more attention," McNeeley told LiveScience.
S
Principle 8i
Human Health and Mortality will be Affected
Human health and mortality rates will be affected to different degrees in specific regions of the world as a result of climate change. Although cold-related deaths are predicted to decrease, other risks are predicted to rise. The incidence and geographical range of climate-sensitive infectious diseases—such as malaria, dengue fever, and tick-borne diseases—will increase. Drought-reduced crop yields, degraded air and water quality, and increased hazards in coastal and low-lying areas will contribute to unhealthy conditions, particularly for the most vulnerable populations.
The wide range of climate-related challenges facing every community are enormous and may appear at times to be overwhelming. The U.S. and other militaries around the world recognize climate change as a serious, potentially catastrophic national and global security threat. Read More…
Human Health and Mortality will be Affected
Human health and mortality rates will be affected to different degrees in specific regions of the world as a result of climate change. Although cold-related deaths are predicted to decrease, other risks are predicted to rise. The incidence and geographical range of climate-sensitive infectious diseases—such as malaria, dengue fever, and tick-borne diseases—will increase. Drought-reduced crop yields, degraded air and water quality, and increased hazards in coastal and low-lying areas will contribute to unhealthy conditions, particularly for the most vulnerable populations.
The wide range of climate-related challenges facing every community are enormous and may appear at times to be overwhelming. The U.S. and other militaries around the world recognize climate change as a serious, potentially catastrophic national and global security threat.
Being aware of the complex, diverse issues is the first step toward building robust, resilient communities and protecting ecosystems. Recently, the Preventive Medicine community, which has years of communicating “bad news” about health and environmental risks to relevant organizations and agencies, began to tackle the health impacts of climate change with a special issue of the American Journal of Preventive Medicine. One article is titled “Community-Based Adaptation to the Health Impacts of Climate Change” by Kristie Ebi and Jan Semenza. Their abstract reads:
“The effects of and responses to the health impacts of climate change will affect individuals, communities, and societies. Effectively preparing for and responding to current and projected climate change requires ongoing assessment and action, not a one-time assessment of risks and interventions. To promote resilience to climate change and other community stressors, a stepwise course of action is proposed for community-based adaptation that engages stakeholders in a proactive problem solving process to enhance social capital across local and national levels. In addition to grassroots actions undertaken at the community level, reducing vulnerability to current and projected climate change will require top-down interventions implemented by public health organizations and agencies.”
Climate Change and Health Issues in Alaska
Alaska Natives
Ground under home in Shishmaref, Alaska collapsing from erosion. Credit: Alaska Conservation Foundation (2010) Exit
Alaska is home to 229 federally recognized tribes that are already experiencing the impacts of climate change in their everyday lives.[3] Alaska Native peoples depend economically, nutritionally, and culturally on fishing and hunting animals, including polar bears, walruses, seals, caribou, and fish. As the supply of fish and game decline, they are likely to travel onto thinning ice in search of food and are being forced to seek alternative food sources. Arctic plants and animals, including those harvested as subsistence food, are also at higher risk for diseases in a warming climate, further affecting food availability and human health.
Locations of 12 Native Villages considering relocation. Source: GAO (2009)
The health of native communities is also threatened by loss of clean water, saltwater intrusion, and sewage contamination from thawing permafrost, as well as by the northward expansion of diseases. Warming also increases exposure to pollutants, such mercury and organic pesticides, that have been transported to Arctic regions and are released from thawing soils.
Thawing permafrost, loss of coastal sea ice, sea level rise, and more intense extreme weather events are also increasing erosion and flooding along Alaska's northwestern coast. More than 30 Native villages are either in the process of or in need of relocating their entire village. In Shishmaref, Kivalina, and Newtok, for example, erosion is causing extensive damage, creating new dangers to residents, and deepening pressure to relocate. However, due to high costs and land constraints, tribal communities in Alaska have been experiencing difficulty relocating to safer areas.
Harmful algal blooms—exacerbated by warming ocean temperatures
Source: https://toolkit.climate.gov/case-studies/alaskan-tribes-join-together-assess-harmful-algal-blooms
Pacific oyster seed.
Harmful algal blooms (HABs) have long been a threat in southeast Alaska: the first human deaths attributed to a HAB occured near Sitka, Alaska in 1799, when an outbreak of paralytic shellfish poisoning killed over a hundred members of Alexander Baranof’s crew. An HAB event occurs when nutrients and sunlight are just right and plankton species respond by multiplying especially rapidly. Submarine filter feeders such as clams, cockles, and scallops that take in the plankton can become contaminated with natural, algal-derived toxins. When people eat these shellfish, the toxins can lead to sickness, brain damage, and death.
Increasingly, evidence suggests that warmer ocean temperatures associated with climate change have contributed to worldwide increases in the duration, frequency, and geographical distribution of HABs. As ocean temperatures rise, increases in HAB outbreaks are expected to worsen over the next few decades. In response, researchers, shellfish growers, and managers must begin to investigate adaptation strategies that can increase their resilience and their capacity to endure climate-driven changes in HAB events. The development of successful adaptation strategies will require an understanding of where and when HABs are likely to occur in a warmer climate.
A partnership to monitor HABs
Although the State of Alaska regularly tests commercial shellfisheries for toxins, they do not test recreational and subsistence shellfisheries. Toxin levels on beaches used for recreational purposes are also unmonitored. In October 2013—after two cases of paralytic shellfish poisoning in Sitka—regional tribal communities formed the Southeast Alaska Tribal Toxins (SEATT) partnership to combat the risks of HABs to subsistence shellfish harvesters.
Southeast Alaska Tribal Toxins (SEATT) partner locations. Click the image for a larger view.
The SEATT partnership seeks to bring tribes in southeastern Alaska together to assess the beaches and shellfish that the state cannot test, increasing access to subsistence resources for tribal members. To date, 11 of the 17 Tribal Nations located in southeast Alaska have joined the partnership. Training and technical assistance for the SEATT partnership is provided by the National Oceanic and Atmospheric Administration's (NOAA) Marine Biotoxin Programs in Seattle, Washington, and Charleston, South Carolina. Additional technical support comes from the Washington State Department of Health Biotoxin Program, the University of Alaska Fairbanks School of Ocean Fisheries and Science, and the Southeast Alaska Regional Dive Fisheries Association. Funding for this partnership has been provided primarily by three federal sources: the U.S. Environmental Protection Agency's Indian General Assistance Program, the U.S. Bureau of Indian Affairs' Climate Change Program, and the Administration for Native Americans' Environmental Regulatory Enhancement Program.
Eyes on the water
Jennifer Hanlon, Environmental Coordinator for the Central Council Tlingit and Haida Indian Tribes of Alaska, uses a microscope to identify phytoplankton and algal species.
At workshops organized through the SEATT partnership, environmental staff from participating tribes learn to use phytoplankton nets, filtering apparatus, and identification tools. Manuals and training resources are distributed via DVD to participating tribes and area communities. These resources can also be accessed from the Southeast Alaska Tribal Ocean Research website (see link in sidebar, under Additional Resources).
Baseline data collection includes weekly phytoplankton species identification and quantification, collection of filtered water samples to analyze for cellular toxins, and recording of environmental parameters. In addition to hosting recorded data on the partnership's website, data is also included in the NOAA SoundToxin Database and the Phytoplankton Monitoring Network to help track the growing threat nationwide.
With “eyes on the water” each week, SEATT members can advise their communities of the potential dangers of local shellfish. Each SEATT community uses the data collected to assess both their local and regional vulnerability to HAB events.
A new testing laboratory saves time and money
Digital microscope used to ID and determine cell density.
By mandate, shellfish tissue must be analyzed within seven days of sample harvest. For southeast Alaskan commercial harvesters, there was no local laboratory that could consistently meet the stringent requirements; samples had to be sent to Anchorage for the required testing. Sample collection, transportation to a lab in Anchorage, and lab analysis can take three to four days, without weather delays—delays that are commonplace in southeast Alaska. Additionally, the boat and plane transport needed to carry the samples is expensive.
To better serve southeast Alaskan commercial shellfish harvesters—as well as to provide the first opportunity for subsistence shellfish harvesters to test their beaches—the Sitka Tribe of Alaska plans to open a shellfish testing laboratory, already in development. The lab will be able to text for toxins using non-regulatory methods by the end of 2015, and will be ready for testing on a regulatory level in the spring of 2017. This new lab will use a recently approved Interstate Shellfish Sanitation Conference (ISSC) receptor binding assay to assess the toxin levels in shellfish. The lab will also be used to conduct regulatory sampling using additional techniques for more species and concerns over time.
Benefits and future expansion
Knowing with confidence when traditional marine foods like shellfish can be harvested safely allows southeast Alaska tribes to continue to enjoy this important cultural icon. Perhaps more important than simple enjoyment, however, is the increased access to local food sources. Subsistence food is relied on heavily in southeast Alaska, where the cost of imported goods is high. As Sitka Tribal Chairman Michael Baines notes, "The Sitka Tribal Council is very concerned about rising ocean temperatures, but is very pleased to have the Tribe's new lab and its ability to detect harmful algal blooms and associated toxins in traditional foods."
Phytoplankton nets used to collect samples for identification.
The weekly plankton monitoring is being developed into a forecasting tool in which rising water temperatures can be linked to thresholds when HAB events become more likely. A proposal has been submitted for additional Bureau of Indian Affairs climate program funding to map algal cysts beds to determine HAB potential and additional control options. Results will be used to develop subsistence shellfish management plans based on sampling data. Coordination has begun with local and state health departments to improve awareness of the dangers of untested shellfish.
The growing number of tribes involved in the SEATT partnership can also leverage their experience with the partnership as they begin to face other climate impacts together. Using their diverse experiences, they may be able to generate innovative solutions to a variety of problems linked to the rapid warming of lands and waters being experienced in southeastern Alaska.
References
- Dale, B., M. Edwards, and P. C. Reid, 2006: Climate change and harmful algal blooms. Ecology of Harmful Algae, Ecological Studies, Vol. 189, Springer, 367–378.
- Edwards, M., D. G. Johns, S. C. Leterme, E. Svendsen, and A. J. Richardson, 2006: Regional climate change and harmful algal blooms in the northeast Atlantic. Limnol. Oceanogr., 51, 820–829.
- Moore, S. K., V. L. Trainer, N. J. Mantua, M. S. Parker, E. A. Laws, L. C. Backer, and L. E. Fleming, 2008: Impacts of climate variability and future climate change on harmful algal blooms and human health. Environmental Health, 7(Suppl 2), S4, DOI:doi:10.1186/1476-069X-7-S2-S4.
- Paerl, H. W., and J. Huisman, 2008: Blooms like it hot. Science, 320, 57–58, DOI:10.1126/science.1155398.
- Pörtner, H. O., and A. P. Farrell, 2008: Physiology and climate change. Science, 322, 690–692, DOI:10.1126/science.1163156.
For good summaries of climate change impacts on human health, click the buttons below
Around the World: Climate change affects human communities. So does the mining of fossil fuels, which cause climate change. For information on those impacts, visit these sites:
Eight Ways That Climate Change Hurts Humans
From floods and droughts to increases in violent conflict, climate change is taking a toll on the planet's population
By Sarah Zielinski
SMITHSONIAN.COM
APRIL 10, 2014
Source: http://www.smithsonianmag.com/science-nature/eight-ways-climate-change-hurts-humans-180950475/?no-ist
As climate change makes wet places wetter and dry areas drier, the frequency of drought is expected in increase in certain locations. Droughts, such as this one in Kenya in 2006, can increase food insecurity, especially among the poor. (Brendan Cox/Oxfam/)
It can be easy to think of climate change as a far-off, indirect threat that some future human population will have to overcome. And that even then, the effects of climate change won’t be too bad, or that they won’t hurt people. But as the latest Intergovernmental Panel on Climate Change report, Climate Change 2014: Impacts, Adaptation and Vulnerability, emphasizes, the effects of climate change already can be seen, and members of the current human population already are its victims.
Climate change will hurt and even kill humans in a stunning variety of ways. Here are nine (sometimes unexpected) ways climate change will negatively affect people:
Heat waves: Extreme heat can be deadly, particularly among the poor who may not have the luxury of retreating to air-conditioned rooms. In Australia, for example, the number of dangerously hot days is expected to rise from its current average of four to six days per year to 33 to 45 by 2070. That will translate to more deaths: About 500 people died because of heat in Australian cities in 2011; the Australian government has projected 2,000 deaths per year by the middle of this century.
Floods: Climate change tends to make wet areas wetter and dry areas drier, and so there will be an increase in both flooding and droughts. Flooding is one of the most common natural disasters. Floods displace people from their homes, damage and destroy infrastructure and buildings, and take a toll on an economic level. In 2011 alone, 112 million people worldwide were affected by floods, and 3140 people were killed.
Drought: Unlike a flood, drought is rarely a direct killer. But extremely dry conditions that last for months or years can lead to food and water shortages and rising food prices, which can contribute to conflict. Droughts also have huge economic costs, even in developed countries. New Zealand, for instance, lost more than $3 billion from 2007-2009 because of reduced farm output from drought.
Fire: Increased heat increases fire risk, and climate change is expected to bring more wildfires. The current California drought, for instance, has raised the risk of “explosive” wildfires. And it’s not just burns and injuries from the fire that are the problems. “Smoke from forest fires has been linked…with increased mortality and morbidity,” the IPCC authors write in Chapter 11, “Human Health: Impacts, Adaptation, and Co-Benefits” [pdf].
Crop declines and food shortages: Extreme weather events, such as floods and droughts, will lead to declines in some crops in some areas. While this might be an inconvenience for people in developed countries when it comes to foods like limes and avocados, the situation will be far more dire when it comes to crops like corn and wheat and in countries that already struggle to feed their populations. Food shortages and increases in food prices, which increase the number of malnourished people, are a particular concern in those places that already suffering from food insecurity, such as large portions of Africa.
Infectious diseases: “Climate may act directly by influencing growth, survival, persistence, transmission or virulence of pathogens,” the IPCC scientists write in Chapter 11. Mosquitoes are sensitive to climate—as temperatures rise, they'll find favorable habitats in places that were once too cool for them to live, such as higher latitudes and altitudes. The diseases they transmit, such as malaria, dengue fever, and chikungunya fever, will spread with them.
Studies show that even a small amount of warming can increase malaria transmission under the right conditions. Dengue fever is another worry; it’s increased 30-fold in the last 50 years. And thanks to infected travelers' ability to move across the globe, chikungunya fever has already spread from Africa and Asia to the Caribbean, and may be poised to cross into the mainland Americas—a warming climate will exacerbate this new-found lack of isolation.
Food- and water-borne diseases, too, are a concern. For example, heavy rainfall, which will continue to increase as climate changes, can promote the transmission of water-borne diseases, such cholera and others caused by Vibrio bacteria, particularly in places where there aren’t good methods for disposing of human waste.
Mental illness: Climate change can increase stress, and that is a problem when it comes to mental health. “Harsher weather conditions such as floods, droughts, and heat waves tend to increase the stress on all those who are already mentally ill, and may create sufficient stress for some who are not yet ill to become so,” the IPCC researchers write in Chapter 11.
"When you have an environmental insult, the burden of mental health disease is far greater than the physical," Steven Shapiro, a Baltimore psychologist who directs the program on climate change, sustainability and psychology for the nonprofit Psychologists for Social Responsibility (PsySR), told LiveScience earlier this year. "Survivors can have all sorts of issues: post traumatic stress disorder, depression, anxiety, relationship issues, and academic issues among kids." Slow-developing events like droughts have even been linked to increases in suicide.
Violence and conflict: Human violence rarely has a single cause, but many of the effects of climate change have the potential to contribute to conflict—water and food shortages, soil degradation that makes land less suitable for agriculture, the movement of people as they migrate from lands made less habitable. “Climate change can indirectly increase risks of violent conflicts in the form of civil war and inter-group violence by amplifying well-documented drivers of these conflicts such as poverty and economic shocks,” researchers write in the report’s Summary for Policymakers [pdf].
These aren't doomsday scenarios; this isn't fearmongering—we're already seeing an uptick in every item on this list. So anyone hoping to avoid the effects of climate change may be out of luck.
S
Leading Health Experts Call For Fossil Fuel Divestment to Avert Climate Change
Source: http://time.com/3935564/health-experts-fossil-fuel-divestment/
Getty Images
'Divestment rests on the premise that it is wrong to profit from an industry whose core business threatens human and planetary health'
More than 50 of the world’s leading doctors and health researchers called on charities to divest from fossil fuel companies in an open letter Thursday. The letter, published in the Guardian, argues that climate change poses a dire risk to public health and that fossil fuel companies are unlikely to take action to reduce carbon emissions without prodding.
“Divestment rests on the premise that it is wrong to profit from an industry whose core business threatens human and planetary health,” the health experts wrote. The case for divestment brings “to mind one of the foundations of medical ethics—first, do no harm.”
The letter is the latest show of support for efforts to halt climate change from the medical community. Recent research has outlined a variety of public health issues caused by climate change, from heath stroke deaths to increased asthma rates. Just this week a study in The Lancet outlined how climate change could erode 50 years of health advances.
Read More: How College Kids Helped Divest $50 Billion From Fossil Fuels
The open letter alluded to those impacts and suggested that divestment would be the best way for global charities to address them. Engaging with fossil fuel companies’ boards has not been shown to work, the researcher wrote, likening the oil industry to the tobacco industry.
“Our primary concern is that a decision not to divest will continue to bolster the social licence of an industry that has indicated no intention of taking meaningful action,” researchers wrote.
The long list of signatories include the editors of The Lancet and BMJ, leading medical journals, as well as medical professors from across the United Kingdom.The letter specifically calls on the Wellcome Trust and the Gates Foundation, two nonprofits that are leading contributors to global health causes, to divestment their multi-billion endowments from fossil fuel companies. Together the companies control total endowments worth more than $70 billion.
S
Principle 8j
What Difference Does Half a Degree in Warming Make?
What's the difference between a two-degree world and a 1.5-degree world? The Paris climate conference in 2015 pledged not just to keep warming “well below 2 °C,” but also to "pursue efforts" to limit warming to 1.5 °C.
But how much of a difference can half a degree Celsius make? First, let's do the conversion to °F since that's the units used in the U.S.: 2 °C = 3.6°F and 1.5 °C = 2.7 °F.
So in degrees Fahrenheit, we're talking about a difference of less than 1°F (.9 °F to be exact). That doesn't sound like much of a difference. But adding half a degree of heat to the world's climate system turns out to make an enormous difference. Here's what the science says:
What Difference Does Half a Degree in Warming Make?
Hot Weather
A study last year by Erich Fischer of the Institute for Atmospheric and Climate Science in Zurich found that the risk of what was “once in a thousand days” hot weather has already increased fivefold. His modelling suggests that it will double again at 1.5 degrees and double once more as we go from 1.5 to 2 degrees. The probability of even more extreme events increases even faster.
At two degrees, parts of southwest Asia, including well-populated regions of the Persian Gulf and Yemen, may become literally uninhabitable without permanent air conditioning.
Droughts
The same will be true for droughts, says Carl-Friedrich Schleussner of the Potsdam Institute for Climate Impact Research in Germany. Last year, he reported that the extra half-degree would produce dramatic increases in the likely length of dry spells over wide areas of the globe, including the Mediterranean, Central America, the Amazon basin, and southern Africa, with resulting declines in river flows from a third to a half. Schleussner concluded that going from 1.5 to 2 degrees “marks the difference between events at the upper limit of present-day natural variability and a new climate regime, particularly in tropical regions.”
Famines
Some researchers predict a massive decline in the viability of food crops critical for human survival. The extra half-degree could cut corn yields in parts of Africa by half, says Bruce Campbell of the International Center for Tropical Agriculture. Schleussner found that even in the prairies of the U.S., the risk of poor corn yields would double.
Ecosystems
Ecosystems would feel the difference too. Take tropical coral reefs, which already regularly come under stress because of high ocean temperatures, suffering “bleaching” especially during El Nino events – as happened on the Great Barrier Reef in Australia this year. Most can now recover when the waters cool again, but today’s exceptional temperature may soon become the new normal. “Virtually all tropical coral reefs are projected to be at risk of severe degradation due to temperature-induced bleaching from 2050 onwards,” as warming slips past 1.5 degrees, reports Schleussner.
By some estimates, curbing warming at 1.5 degrees could be sufficient to prevent the formation of an ice-free Arctic in summer, to save the Amazon rainforest, and to prevent the Siberian tundra from melting and releasing planet-warming methane from its frozen depths. It could also save many coastal regions and islands from permanent inundation by rising sea levels, particularly in the longer run.
In 2100, the difference in sea level rise between 1.5 and 2 degrees would be relatively small: 40 centimeters versus 50 centimeters. But centuries later, as the impact of warmer air temperatures on the long-term stability of the great ice sheets of Greenland and Antarctica takes hold, it would be far greater. Michiel Schaeffer of Climate Analytics, a Berlin-based think tank, calculates that by 2300, two degrees would deliver sea level rise of 2.7 meters, while 1.5 degrees would limit the rise to 1.5 meters.
Source: http://e360.yale.edu/feature/what_would_a_global_warming_increase_15_degree_be_like/3007/
Principle 8k
A Summary of Impacts
Principle 8l
Local Relevance
Alaska’s huge climate mystery
By Chris Mooney for the Washington Post
Source: https://www.washingtonpost.com/news/energy-environment/wp/2016/06/03/alaskas-huge-climate-mystery-and-its-global-consequences/?utm_term=.e6c848ae48f6
In recent years, climate scientists have grown increasingly concerned about a carbon problem in the far north.
The fear is that with the higher latitudes of the planet warming extremely rapidly, that heat itself, and some of its consequences — such as raging wildfires in northern forests — could unleash a climate disaster. Perennially frozen northern soils, known as permafrost, contain enormous amounts of carbon because the slow and cold chemistry of the Arctic makes them the repository of thousands of years of frozen plant remains. Warming could cause this plant matter to break down, be decomposed by bacteria and emit ancient carbon to the atmosphere in the form of carbon dioxide and methane.
And the amounts of carbon involved are enormous — one common estimate is that there’s more than twice as much carbon stored in northern permafrost as there is currently wafting about the planet’s atmosphere. Read more…
Alaska’s huge climate mystery
Now, though, a major and surprising new report from the U.S. Geological Survey would appear to undercut, significantly, this worry, at least for one key northern region: the U.S. state of Alaska. In the process, the document raises deep questions about what the true carbon consequences of Alaska’s ongoing warming will be — a mystery whose solution may also implicate still greater carbon stores across Arctic regions in Canada and Siberia.
Alaska alone, though, is massive enough. While it makes up 18 percent of the United States’ total area, the state stores 53 percent of all of the nation’s carbon, much of it in permafrost below the ground, the USGS study reports. Indeed, it adds that wildfires in Alaska give off more greenhouse gases to the atmosphere annually than all fires in the Lower 48 states.
Clearly, any change to this carbon in one direction — shifting it from the land to the atmosphere — would be disastrous. But is that happening?
To better understand the issues at stake here, it may help to have a quick refresher on some concepts that climate scientists live and breathe but that the rest of us do not. Researchers say that a particular region — in this case, Alaska — is a carbon “sink” if its lands, plants, waters and so on are pulling more carbon dioxide and other greenhouse gases out of the atmosphere than they are putting into it. And conversely, researchers say that an area is a carbon “source” if the net result of everything happening there, across often very diverse types of landscapes and ecosystems, leads to more carbon ending up in the atmosphere.
Here’s where the USGS report comes in — and what’s new about it. Attempting to quantify the vast amounts of carbon stored in Alaska’s trees, waters and soils, the study finds that Alaska is a net carbon repository, or sink. The state is subtracting a relatively small amount of carbon from the atmosphere at the moment, about 3.7 million metric tons per year.
That’s good news for both the United States and the planet. But it’s just the beginning. The report also finds — perhaps more controversially — that heading out to the year 2100, the state of Alaska as a whole should wind up pulling even more carbon back out of the atmosphere than it is now, rather than expelling more of it there. In other words, the sink should strengthen.
The reason is that while Alaska’s boreal forest region is expected to see bigger and more intense wildfires that send up large amounts of carbon stored in trees and soils — and while permafrost will certainly degrade to some extent — other parts of Alaska are simultaneously expected to green up. There will be more carbon dioxide in the air (plants dig it), and less really cold weather, among other factors, leading to a phenomenon that has often been dubbed “Arctic greening.”
“The simulations show that the tundra increases in biomass, and carbon storage. And that’s both in northern and western Alaska,” said David McGuire, a U.S. Geological Survey researcher who edited the extensive report, which contains contributions from multiple scientists, along with the USGS’s Zhiliang Zhu.
For those who have been following the climate debate closely, it’s an unexpected conclusion — and one that climate change skeptics and doubters might trumpet as a classic case of an alarmist climate scenario not coming to pass after all. If you dig down into the fine print, though, there remain many uncertainties — and many continuing reasons for concern about what will happen to stored carbon in Alaska and across the frozen north.
“What I don’t want people to think is, everything’s all rosy,” McGuire said. “We’re not saying that.”
First of all, McGuire and Zhu noted in an interview, the study necessarily omitted some carbon sources that are not well understood, such as methane emissions from lakes. Their inclusion could, conceivably, tip the balance back into one where Alaska is adding carbon to the atmosphere, at least when it comes to assessing the state’s carbon balance in the present.
Or as the study puts it: “It is important to recognize that [methane] emissions from lakes have not been considered in this assessment, and it is likely that Alaska would be a source of greenhouse gases under all climate simulations if these emissions were considered in the assessment.”
Similarly, even though Alaska is storing carbon as a whole, some of the carbon that goes up into the atmosphere does so in the form of methane, a particularly powerful greenhouse gas. And there’s enough methane coming from wetlands in Alaska that it causes a modest net warming effect on the atmosphere anyway, McGuire and Zhu said. Thus, paradoxically, in this case a carbon sink can cause the planet to warm up slightly.
Some other Alaska and permafrost researchers, not involved in the current study, also said that there remain reasons for concern here.
“It’s important to remember that these models are predicting both losses of soil carbon as well as new plant uptake and so it’s going to be critical to assess whether stimulated plant uptake by rising CO2 and the other factors really will compensate for soil carbon losses, because that’s the process that offsets emissions to the atmosphere,” said Ted Schuur, a permafrost researcher at Northern Arizona University in Flagstaff. “This is the same question in global scale models too — and the jury is still out whether plant stimulation by rising CO2 will maintain over this century.”
“In my view, nobody really has a great understanding of what will happen to permafrost carbon as permafrost thaws over the coming century,” added Max Holmes, a permafrost researcher at the Woods Hole Research Center. “What is clear, however, is that the amount of carbon in permafrost in the Arctic and boreal region dwarfs the amount of carbon in vegetation.”
Thus, Holmes said that he remains concerned that permafrost thaw could outpunch plant growth from a carbon perspective. “I think it would be a huge mistake for policymakers to bank on the Arctic mitigating global warming over the coming century — the opposite still seems more likely to me,” he added.
Indeed, an expert assessment of the views of a large number of Arctic researchers recently found they tend toward the belief that “Arctic and boreal biomass should not be counted on to offset permafrost carbon release and… that the permafrost region will become a carbon source to the atmosphere by 2100 regardless of warming scenario.” Clearly, this tug of war — between permafrost pouring carbon into the atmosphere and new plant growth pulling it back again — will be a crucial determinant of how the Arctic shapes our planetary future.
Thus, the new U.S. Geological Survey study certainly does present surprisingly good news for Alaska’s role in climate change — but it also raises a lot of questions, as its authors fully admit.
“This is big progress that we’ve made in terms of getting this assessment out, but it shouldn’t be the last word on the Alaska problem,” McGuire said.
Click the button below to learn what the National Climate Assessment says about Alaska
Click the button below to learn more about
climate change impacts in Alaska
Overview
Alaska is the largest state in the United States, accounting for about 20% of the total area of the United States and more than twice the land area of Texas. Alaska includes lands on both sides of the Arctic Circle, which makes the United States an Arctic nation. The state spans a wide range of climatic and ecological conditions that include rainforests, glaciers, boreal forest, tundra, peatlands, and meadows. Alaska contains 16 national wildlife refuges spanning 76 million acres and hosts 60% of the total area managed by the National Park Service, including the largest U.S. National Park (Wrangell-St. Elias with 13.2 million acres).
Over the past 60 years, the average temperature across Alaska has increased by approximately 3°F. This increase is more than twice the warming seen in the rest of the United States. Warming in the winter has increased by an average of 6°F and has led to changes in ecosystems, such as earlier breakup of river ice in the spring. As the climate continues to warm, average annual temperatures in Alaska are projected to increase an additional 2 to 4°F by the middle of this century. Precipitation in Alaska is projected to increase during all seasons by the end of this century. Despite increased precipitation, the state is likely to become drier due to greater evaporation caused by warming temperatures and longer growing seasons.
Rising temperatures may provide some benefits in Alaska, such as a longer growing season for agricultural crops, increased tourism, and access to natural resources that are currently inaccessible due to ice cover, like offshore oil. However, climate change is also having adverse effects on many ecosystems and species, and is creating new hardships for Native Alaskans.
Permafrost
Permafrost is frozen ground that is typically located a few feet below the soil surface in extremely cold regions. Eighty percent of Alaska's surface lies above permafrost. Permafrost typically remains frozen year-round, but as air temperatures rise, permafrost is thawing in many areas. As permafrost thaws, ice in the permafrost melts and can cause the soil above to sink, resulting in ground subsidence and damage to roads, homes, and other structures. The impacts of melting permafrost on transportation, forests, other ecosystems, and the economy could have widespread implications for Alaskans.
Climate change leads to more permafrost thaw and disruptions to freeze-thaw cycles that can increase frost heaves and subsidence. This can potentially cause damage to transportation infrastructure in Alaska, including highways, railroads, and airstrips. Uneven sinking of the ground in response to permafrost thaw is likely to add significant costs to the maintenance and repair of transportation infrastructure and buildings. Many of Alaska's highways are built in permafrost areas and are subject to damage if the permafrost thaws. Additionally, warming leads to a shorter period when ice roads are usable and a shorter season during which oil and gas exploration on the tundra can occur.
Alaska highways susceptible to permafrost. Source: U.S. Arctic Research Commission (2003)[4]
Ecosystems
Climate change is causing changes in lakes, ponds, wetlands, plant composition, and wildfires that impact human health, wildlife, and ecosystems. Lakes are changing size, with most lakes shrinking in area in the southern portion of the state. Surface waters and wetlands provide breeding habitat for millions of waterfowl and shorebirds that winter in the lower 48 states. These wetland ecosystems and wildlife resources are also important to Alaska Natives who hunt and fish for food.
Two pairs of aerial photographs of pond areas in Alaska. The two images on the left show the pond areas in 1951 and images on the right show the same pond areas in 2000. The pond areas shown on top shrunk from 180 to 10 acres, and the pond areas shown in the bottom went from 90 to 4 acres in size. Source: USGCRP (2009)
Lakes get smaller through a combination of increased evaporation caused by warmer temperatures, permafrost thaw which allows lakes to drain more readily, and greater accumulation of decomposing plant material on lake bottoms caused by greater plant growth. In areas where permafrost is discontinuous or fragmented across the landscape, lakes are expected to continue shrinking in area. Some lakes are growing in area because of lateral permafrost thaw, which causes the edges of the lake to collapse inward, thereby increasing the area of the lake. Lake growth is expected to continue in areas underlain with continuous permafrost.
As the climate warms, shrubs are expanding into the tundra. In some areas, shrubs are replacing lichens and other tundra vegetation. Lichens are an important winter food source for caribou, and the loss of lichens can lead to declines in the growth and abundance of these animals. Caribou, in turn, are a critical food source for predators such as bears and wolves, as well as for some Alaska Natives.
In recent years, an increase in large wildfires has been seen in Alaska. Credit: USGCRP (2014)
Higher temperatures and drier conditions increase the risks of drought, wildfire, and insect infestation. Large wildfires have consumed more boreal forest in Alaska in the last ten years than in any other decade recorded, and the area burned annually is projected to double by 2050. Fires change forest habitat, improving conditions for moose and some plant species, but reducing the lichen that caribou rely on in winter. Warmer temperatures are also expected to worsen insect damage to forests across much of the state, which may increase the area of standing dead, highly flammable trees that are especially vulnerable to wildfire.
Oceans and Coasts
Sea ice is frozen seawater that floats on the surface of the ocean. Some sea ice persists from year to year (known as perennial sea ice), often getting thicker as it piles up against Arctic shorelines. Other sea ice is seasonal, melting during the summer and refreezing in winter.
Sea ice extent has, on average, been declining in recent decades. This figure shows the extent from 1979 to 2015. Source: US EPA (2015)
Over the past several decades, perennial sea ice has declined. This decline is, in part, a result of extended periods of above-freezing air or water temperatures. Ocean currents and wind patterns have also played an important role. September 2012 had the lowest sea ice extent (or area of ocean covered by ice) on record, 49 percent below the 1979-2000 average for that month. The September 2014 sea ice extent was nearly 700,000 square miles less than the historical 1979-2000 average for that month - a difference more than twice the size of Texas. The thickness and age of sea ice is also declining throughout the Arctic, with recent measurements indicating a loss of 50% of sea ice since 1979. Climate models project that sea ice will continue to decrease and indicate that the Arctic could be nearly ice free during the late summer by the 2030s.
Diminishing sea ice is opening new opportunities for shipping, oil and gas exploration, tourism, and other economic activities. However, it also creates a pathway for invasive species and habitat loss for a variety of ice-dependent species, including walruses and polar bears. Changes in sea ice can also affect the timing and location of plankton blooms, which can in turn affect the areas where commercial fisheries can thrive. Sea ice along the shoreline and permafrost in coastal areas help to protect human settlements from flooding and erosion. As coast erosion increases due to declining sea ice, residents are becoming more vulnerable.
Alaska Natives
Alaska is home to 229 federally recognized tribes that are already experiencing the impacts of climate change in their everyday lives. Alaska Native peoples depend economically, nutritionally, and culturally on fishing and hunting animals, including polar bears, walruses, seals, caribou, and fish. As the supply of fish and game decline, they are likely to travel onto thinning ice in search of food and are being forced to seek alternative food sources. Arctic plants and animals, including those harvested as subsistence food, are also at higher risk for diseases in a warming climate, further affecting food availability and human health.
Ground under home in Shishmaref, Alaska collapsing from erosion. Credit: Alaska Conservation Foundation (2010)
Locations of 12 Native Villages considering relocation. Source: GAO (2009)
The health of native communities is also threatened by loss of clean water, saltwater intrusion, and sewage contamination from thawing permafrost, as well as by the northward expansion of diseases. Warming also increases exposure to pollutants, such mercury and organic pesticides, that have been transported to Arctic regions and are released from thawing soils.
Thawing permafrost, loss of coastal sea ice, sea level rise, and more intense extreme weather events are also increasing erosion and flooding along Alaska's northwestern coast. More than 30 Native villages are either in the process of or in need of relocating their entire village. In Shishmaref, Kivalina, and Newtok, for example, erosion is causing extensive damage, creating new dangers to residents, and deepening pressure to relocate.[8] However, due to high costs and land constraints, tribal communities in Alaska have been experiencing difficulty relocating to safer areas.
Source: https://www.epa.gov/climate-impacts/climate-impacts-alaska
Principle 8m
Misconceptions about this Principle
The Misconception
Global warming will be good for humans
The misconception or myth goes something like this: “…Two thousand years of published human histories say that warm periods were good for people. It was the harsh, unstable Dark Ages and Little Ice Age that brought bigger storms, untimely frost, widespread famine and plagues of disease.”
The Science
Scientist predict climate change will bring many more costs than benefits.
The science says: climate change will have many more costs than benefits. While it is expected that global warming may bring a few benefits in the short term, it is expected that over the longer term, it will bring few or no benefits to human society and instead will do great harm at considerable cost. Learn more…
Source: https://www.skepticalscience.com/global-warming-positives-negatives.htm
The Science
Scientist predict climate change will bring many more costs than benefits.
The science says: climate change will have many more costs than benefits. While it is expected that global warming may bring a few benefits in the short term, it is expected that over the longer term, it will bring few or no benefits to human society and instead will do great harm at considerable cost.
Source: https://www.skepticalscience.com/global-warming-positives-negatives.htm
- AgricultureWhile CO2 is essential for plant growth, all agriculture depends also on steady water supplies, and climate change is likely to disrupt those supplies through floods and droughts. It has been suggested that higher latitudes – Siberia, for example – may become productive due to global warming, but the soil in Arctic and bordering territories is very poor, and the amount of sunlight reaching the ground in summer will not change because it is governed by the tilt of the earth. Agriculture can also be disrupted by wildfires and changes in seasonal periodicity, which is already taking place, and changes to grasslands and water supplies will impact grazing and welfare of domestic livestock. Increased warming may also have a greater effect on countries whose climate is already near or at a temperature limit over which yields reduce or crops fail – in the tropics or sub-Sahara, for example.
Source: https://www.skepticalscience.com/global-warming-positives-negatives.htm - HealthWarmer winters would mean fewer deaths, particularly among vulnerable groups like the aged. However, the same groups are also vulnerable to additional heat, and deaths attributable to heat waves are expected to be approximately five times as great as winter deaths prevented. It is widely believed that warmer climes will encourage migration of disease-bearing insects like mosquitoes. Malaria (transmitted by mosquitoes) is already appearing in places it hasn’t been seen before.
Source: https://www.skepticalscience.com/global-warming-positives-negatives.htm - Polar MeltingWhile the opening of a year-round ice-free Arctic passage between the Atlantic and Pacific oceans would confer some commercial benefits, these are considerably outweighed by the negatives. Detrimental effects include loss of polar bear habitat and increased mobile ice hazards to shipping. The loss of ice albedo (the reflection of heat), causing the ocean to absorb more heat, is also a feedback loop that furthers warming—with enormous and potentially catastrophic consequences; the warming waters increase glacier and Greenland ice cap melt and raise the temperature of Arctic tundra. Warmer tundra then releases methane, a very potent greenhouse gas (methane is also released from the sea-bed, where it is trapped in ice-crystals called clathrates). Melting of the Antarctic ice shelves is predicted to add further to sea-level rise with no benefits accruing.
Source: https://www.skepticalscience.com/global-warming-positives-negatives.htm - Ocean AcidificationA cause for considerable concern, there appear to be no benefits to the change in pH of the oceans. This process is caused by additional CO2 being absorbed in the water, and may have severe destabilizing effects on the entire oceanic food-chain.
Source: https://www.skepticalscience.com/global-warming-positives-negatives.htm - Melting GlaciersThe effects of glaciers melting are largely detrimental, the principle impact being that one-sixth of the world’s population depends on fresh water supplied each year by natural spring melt and regrowth cycles. Melting glaciers mean those water supplies, used as drinking water and for agriculture, may fail.
Source: https://www.skepticalscience.com/global-warming-positives-negatives.htm - Sea-level RiseMany parts of the world are low-lying and will be severely affected by modest sea rises. Rice paddies are being inundated with salt water, which destroys the crops. Seawater is contaminating rivers as it mixes with fresh water further upstream, and aquifers used for drinking water and agriculture are becoming polluted. Given that the IPCC did not include melt-water from the Greenland and Antarctic ice-caps due to uncertainties at that time, estimates of sea-level rise are feared to considerably underestimate the scale of the problem. There are no proposed benefits to sea-level rise.
Source: https://www.skepticalscience.com/global-warming-positives-negatives.htm - EnvironmentalPositive effects of climate change may include greener rain forests and enhanced plant growth in the Amazon, increased vegetation in northern latitudes and possible increases in plankton biomass in some parts of the ocean. Negative responses may include further growth of oxygen-poor ocean zones, contamination or exhaustion of fresh water, increased incidence of natural fires, extensive vegetation die-off due to droughts, increased risk of coral extinction, decline in global phytoplankton, changes in migration patterns of birds and animals, changes in seasonal periodicity, disruption to food chains and species loss.
Source: https://www.skepticalscience.com/global-warming-positives-negatives.htm - EconomicThe economic impacts of climate change may be catastrophic, while there have been very few benefits projected at all. The Stern report made clear the overall pattern of economic distress, and while the specific numbers may be contested, the costs of climate change were far in excess of the costs of preventing it. Certain scenarios projected in the IPCC AR4 report would witness massive migration as low-lying countries were flooded. Disruptions to global trade, transport, energy supplies and labour markets, banking and finance, investment and insurance, would all wreak havoc on the stability of both developed and developing nations. Markets would endure increased volatility and institutional investors such as pension funds and insurance companies would experience considerable difficulty.
Developing countries, some of which are already embroiled in military conflict, may be drawn into larger and more protracted disputes over water, energy supplies or food, all of which may disrupt economic growth at a time when developing countries are beset by more egregious manifestations of climate change. It is widely accepted that the detrimental effects of climate change will be visited largely on the countries least equipped to adapt, socially or economically.
Source: https://www.skepticalscience.com/global-warming-positives-negatives.htm - Show More
Check your Knowledge of this Principle
To pass this knowledge check you will need to have read the main paragraphs for each topic of the principle.