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”
Living Landscapes: Southeast Region
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”
Southeast and Caribbean Region Impacts
- Introduction
Introduction
The Southeast and Caribbean are exceptionally vulnerable to sea level rise, extreme heat events, hurricanes, and decreased water availability. The geographic distribution of these impacts and vulnerabilities is uneven, since the region encompasses a wide range of natural system types, from the Appalachian Mountains to the coastal plains. It is also home to more than 80 million people and draws millions of visitors every year. In 2009, Puerto Rico hosted 3.5 million tourists who spent $3.5 billion. In 2012, Louisiana and Florida alone hosted more than 115 million visitors.
The region has two of the most populous metropolitan areas in the country (Miami and Atlanta) and four of the ten fastest-growing metropolitan areas. Three of these (Palm Coast, FL, Cape Coral-Fort Myers, FL, and Myrtle Beach area, SC) are along the coast and are vulnerable to sea level rise and storm surge. Puerto Rico has one of the highest population densities in the world, with 56% of the population living in coastal municipalities.
©Richard H. Cohen/Corbis
The Gulf and Atlantic coasts are major producers of seafood and home to seven major ports that are also vulnerable. The Southeast is a major energy producer of coal, crude oil, and natural gas, and is the highest energy user of any of the National Climate Assessment regions.Figure 17.1: Billion Dollar Weather/Climate Disasters
Figure 17.1: This map summarizes the number of times each state has been affected by weather and climate events over the past 30 years that have resulted in more than a billion dollars in damages. The Southeast has been affected by more billion-dollar disasters than any other region. The primary disaster type for coastal states such as Florida is hurricanes, while interior and northern states in the region also experience sizeable numbers of tornadoes and winter storms. For a list of events and the affected states, see: http://www.ncdc.noaa.gov/billions/events. (Figure source: NOAA NCDC).The Southeast’s climate is influenced by many factors, including latitude, topography, and proximity to the Atlantic Ocean and the Gulf of Mexico. Temperatures generally decrease northward and into mountain areas, while precipitation decreases with distance from the Gulf and Atlantic coasts. The region’s climate also varies considerably over seasons, years, and decades, largely due to natural cycles such as the El Niño-Southern Oscillation (ENSO – periodic changes in ocean surface temperatures in the Tropical Pacific Ocean), the semi-permanent high pressure system over Bermuda, differences in atmospheric pressure over key areas of the globe, and landfalling tropical weather systems. These cycles alter the occurrences of hurricanes, tornadoes, droughts, flooding, freezing winters, and ice storms, contributing to climate and weather disasters in the region that have exceeded the total number of billion dollar disasters experienced in all other regions of the country combined (see Figure 17.1).
Source: http://nca2014.globalchange.gov/report/regions/southeast
. - Observed and Projected Climate Change
Observed and Projected Climate Change
Average annual temperature during the last century across the Southeast cycled between warm and cool periods (see Figure 17.3, black line). A warm peak occurred during the 1930s and 1940s followed by a cool period in the 1960s and 1970s. Temperatures increased again from 1970 to the present by an average of 2°F, with higher average temperatures during summer months.
Observed annual average temperature for the Southeast and projected temperatures assuming substantial emissions reductions (lower emissions, B1) and assuming continued growth in emissions (higher emissions, A2). For each emissions scenario, shading shows the range of projections and the line shows a central estimate. The projections were referenced to observed temperatures for the period 1901-1960. The region warmed during the early part of last century, cooled for a few decades, and is now warming again. The lack of an overall upward trend over the entire period of 1900-2012 is unusual compared to the rest of the U.S. and the globe. This feature has been dubbed the “warming hole” and has been the subject of considerable research, although a conclusive cause has not been identified. (Figure source: adapted from Kunkel et al. 20132).
There have been increasing numbers of days above 95°F and nights above 75°F, and decreasing numbers of extremely cold days since 1970. The Caribbean also exhibits a trend since the 1950s, with increasing numbers of very warm days and nights, and with daytime maximum temperatures above 90°F and nights above 75°F. Daily and five-day rainfall intensities have also increased. Also, summers have been either increasingly dry or extremely wet. For the Caribbean, precipitation trends are unclear, with some regions experiencing smaller annual amounts of rainfall and some increasing amounts. Although the number of major tornadoes has increased over the last 50 years, there is no statistically significant trend. This increase may be attributable to better reporting of tornadoes. The number of Category 4 and 5 hurricanes in the Atlantic basin has increased substantially since the early 1980s compared to the historical record that dates back to the mid-1880s. This can be attributed to both natural variability and climate change.Figure 17.4: Projected Change in Number of Days Over 95°F
Projected average number of days per year with maximum temperatures above 95°F for 2041-2070 compared to 1971-2000, assuming emissions continue to grow (A2 scenario). Patterns are similar, but less pronounced, assuming a reduced emissions scenario (B1). (Figure source: NOAA NCDC / CICS-NC).Temperatures across the Southeast and Caribbean are expected to increase during this century, with shorter-term (year-to-year and decade-to-decade) fluctuations over time due to natural climate variability. Major consequences of warming include significant increases in the number of hot days (95°F or above) and decreases in freezing events. Although projected increases for some parts of the region by the year 2100 are generally smaller than for other regions of the United States, projected increases for interior states of the region are larger than coastal regions by 1°F to 2°F. Regional average increases are in the range of 4°F to 8°F (combined 25th to 75th percentile range for A2 and B1 emissions scenarios) and 2°F to 5°F for Puerto Rico.
Figure 17.5: Projected Change in Number of Nights Below 32°F
Projected average number of days per year with temperatures less than 32°F for 2041-2070 compared to 1971-2000, assuming emissions continue to grow (A2 scenario). Patterns are similar, but less pronounced, assuming a reduced emissions scenario (B1). (Figure source: NOAA NCDC / CICS-NC).Projections of future precipitation patterns are less certain than projections for temperature increases. Because the Southeast is located in the transition zone between projected wetter conditions to the north and drier conditions to the southwest, many of the model projections show only small changes relative to natural variations. However, many models do project drier conditions in the far southwest of the region and wetter conditions in the far northeast of the region, consistent with the larger continental-scale pattern of wetness and dryness. For the Caribbean, it is equally difficult to project the magnitude of precipitation changes, although the majority of models show future decreases in precipitation are likely, with a few areas showing increases. In general, annual average decreases are likely to be spread across the entire region. Projections further suggest that warming will cause tropical storms to be fewer in number globally, but stronger in force, with more Category 4 and 5 storms. On top of the large increases in extreme precipitation observed during last century and early this century), substantial further increases are projected as this century progresses.
Source: http://nca2014.globalchange.gov/report/regions/southeast
. - Sea Level Rise Threats
Sea Level Rise Threats
Global sea level rise over the past century averaged approximately eight inches, and that rate is expected to accelerate through the end of this century. Portions of the Southeast and Caribbean are highly vulnerable to sea level rise. How much sea level rise is experienced in any particular place depends on whether and how much the local land is sinking (also called subsidence) or rising, and changes in offshore currents.Figure 17.6: Vulnerability to Sea Level Rise
The map shows the relative risk that physical changes will occur as sea level rises. The Coastal Vulnerability Index used here is calculated based on tidal range, wave height, coastal slope, shoreline change, landform and processes, and historical rate of relative sea level rise. The approach combines a coastal system’s susceptibility to change with its natural ability to adapt to changing environmental conditions, and yields a relative measure of the system’s natural vulnerability to the effects of sea level rise. (Data from Hammar-Klose and Thieler 20011).Large numbers of cities, roads, railways, ports, airports, oil and gas facilities, and water supplies are at low elevations and potentially vulnerable to the impacts of sea level rise. New Orleans (with roughly half of its population living below sea level), Miami, Tampa, Charleston, and Virginia Beach are among those most at risk. As a result of current sea level rise, the coastline of Puerto Rico around Rincón is being eroded at a rate of 3.3 feet per year.
According to a recent study co-sponsored by a regional utility, coastal counties and parishes in Alabama, Mississippi, Louisiana, and Texas, with a population of approximately 12 million, assets of about $2 trillion, and producers of $634 billion in annual gross domestic product, already face significant losses that annually average $14 billion from hurricane winds, land subsidence, and sea level rise. Future losses for the 2030 timeframe could reach $18 billion (with no sea level rise or change in hurricane wind speed) to $23 billion (with a nearly 3% increase in hurricane wind speed and just under 6 inches of sea level rise). Approximately 50% of the increase in the estimated losses is related to climate change. The study identified $7 billion in cost-effective adaptation investments that could reduce estimated annual losses by about 30% in the 2030 timeframe.
The North Carolina Department of Transportation is raising the roadbed of U.S. Highway 64 across the Albemarle-Pamlico Peninsula by four feet, which includes 18 inches to allow for higher future sea levels.,, Louisiana State Highway 1, heavily used for delivering critical oil and gas resources from Port Fourchon, is literally sinking, resulting in more frequent and more severe flooding during high tides and storms. The Department of Homeland Security estimated that a 90-day shutdown of this road would cost the nation $7.8 billion.
Figure 17.7: Highway 1 to Port Fourchon: Vulnerability of a Critical Link for U.S. Oil
Highway 1 in southern Louisiana is the only road to Port Fourchon, whose infrastructure supports 18% of the nation’s oil and 90% of the nation’s offshore oil and gas production. Flooding is becoming more common on Highway 1 in Leeville (inset photo from flooding in 2004), on the way to Port Fourchon. (Figure and photo sources: Louisiana Department of Transportation and Development; State of Louisiana 2012).Sea level rise increases pressure on utilities – such as water and energy – by contaminating potential freshwater supplies with saltwater. Such problems are amplified during extreme dry periods with little runoff. Uncertainties in the scale, timing, and location of climate change impacts can make decision-making difficult, but response strategies, especially those that try to anticipate possible unintended consequences, can be more effective with early planning. Some utilities in the region are already taking sea level rise into account in the construction of new facilities and are seeking to diversify their water sources.
There is an imminent threat of increased inland flooding during heavy rain events in low-lying coastal areas such as southeast Florida, where just inches of sea level rise will impair the capacity of stormwater drainage systems to empty into the ocean. Drainage problems are already being experienced in many locations during seasonal high tides, heavy rains, and storm surge events. Adaptation options that are being assessed in this region include the redesign and improvement of storm drainage canals, flood control structures, and stormwater pumps.
As temperatures and sea levels increase, changes in marine and coastal systems are expected to affect the potential for energy resource development in coastal zones and the outer continental shelf. Oil and gas production infrastructure in bays and coves that are protected by barrier islands, for example, are likely to become increasingly vulnerable to storm surge as sea level rises and barrier islands deteriorate along the central Gulf Coast. The capacity for expanding and maintaining onshore and offshore support facilities and transportation networks is also apt to be affected.Figure 17.8: South Florida: Uniquely Vulnerable to Sea Level Rise
Sea level rise presents major challenges to South Florida’s existing coastal water management system due to a combination of increasingly urbanized areas, aging flood control facilities, flat topography, and porous limestone aquifers. For instance, South Florida’s freshwater well field protection areas (left map: pink areas) lie close to the current interface between saltwater and freshwater (red line), which will shift inland with rising sea level, affectingwater managers’ ability to draw drinking water from current resources. Coastal water control structures (right map: yellow circles) that were originally built about 60 years ago at the ends of drainage canals to keep saltwater out and to provide flood protection to urbanized areas along the coast are now threatened by sea level rise. Even today, residents in some areas such as Miami Beach are experiencing seawater flooding their streets (lower photo). (Maps from The South Florida Water Management District.1 Photo credit: Luis Espinoza, Miami-Dade County Department of Regulatory and Economic Resources).Sea level rise and storm surge can have impacts far beyond the area directly affected. Homes and infrastructure in low areas are increasingly prone to flooding during tropical storms. As a result, insurance costs may increase or coverage may become unavailable and people may move from vulnerable areas, stressing the social and infrastructural capacity of surrounding areas. This migration also happens in response to extreme events such as Hurricane Katrina, when more than 200,000 migrants were temporarily housed in Houston and 42% indicated they would try to remain there.
Furthermore, because income is a key indicator of climate vulnerability, people that have limited economic resources are more likely to be adversely affected by climate change impacts such as sea level rise. In the Gulf region, nearly 100% of the “most socially vulnerable people live in areas unlikely to be protected from inundation,” bringing equity issues and environmental justice into coastal planning efforts.
Ecosystems of the Southeast and Caribbean are exposed to and at risk from sea level rise, especially tidal marshes and swamps. Some tidal freshwater forests are already retreating, while mangrove forests (adapted to coastal conditions) are expanding landward. The pace of sea level rise will increasingly lead to inundation of coastal wetlands in the region. Such a crisis in land loss has occurred in coastal Louisiana for several decades, with 1,880 square miles having been lost since the 1930s as a result of natural and man-made factors., With tidal wetland loss, protection of coastal lands and people against storm surge will be compromised.
Homes and infrastructure in low-lying areas are increasingly vulnerable to flooding due to storm surge as sea level rises. Courtesy of NOAA.
Reduction of wetlands also increases the potential for losses of important fishery habitat. Additionally, ocean warming could support shifts in local species composition, invasive or new locally viable species, changes in species growth rates, shifts in migratory patterns or dates, and alterations to spawning seasons., Any of these could affect the local or regional seafood output and thus the local economy.
In some southeastern coastal areas, changes in salinity and water levels due to a number of complex interactions (including subsidence, availability of sediment, precipitation, and sea level rise) can happen so fast that local vegetation cannot adapt quickly enough and those areas become open water. Fire, hurricanes, and other disturbances have similar effects, causing ecosystems to cross thresholds at which dramatic changes occur over short time frames.
The impacts of sea level rise on agriculture derive from decreased freshwater availability, land loss, and saltwater intrusion. Saltwater intrusion is projected to reduce the availability of fresh surface and groundwater for irrigation, thereby limiting crop production in some areas. Agricultural areas around Miami-Dade County and southern Louisiana with shallow groundwater tables are at risk of increased inundation and future loss of cropland with a projected loss of 37,500 acres in Florida with a 27-inch sea level rise, which is well within the 1- to 4-foot range of sea level rise projected by 2100.Figure 17.9: Local Planning
Miami-Dade County staff leading workshop on incorporating climate change considerations in local planning. (Photo credit: Armando Rodriguez, Miami-Dade County).There are basically three types of adaptation options to rising sea levels: protect (such as building levees or other “hard” methods), accommodate (such as raising structures or using “soft” or natural protection measures such as wetlands restoration), and retreat., Individuals and communities are using all of these strategies. However, regional cooperation among local, state, and federal governments can greatly improve the success of adapting to impacts of climate change and sea level rise. An excellent example is the Southeast Florida Regional Compact. Through collaboration of county, state, and federal agencies, a comprehensive action plan was developed that includes hundreds of actions and special Adaptation Action Areas.
Source: http://nca2014.globalchange.gov/report/regions/southeast
. - Increasing Temperatures
Increasing Temperatures
The negative effects of heat on human cardiovascular, cerebral, and respiratory systems are well established. Atlanta, Miami, New Orleans, and Tampa have already had increases in the number of days with temperatures exceeding 95ºF, during which the number of deaths is above average. Higher temperatures also contribute to the formation of harmful air pollutants and allergens. Ground-level ozone is projected to increase in the 19 largest urban areas of the Southeast, leading to an increase in deaths. A rise in hospital admissions due to respiratory illnesses, emergency room visits for asthma, and lost school days is expected.Figure 17.10: Ground-level Ozone
Ground-level ozone is an air pollutant that is harmful to human health and which generally increases with rising temperatures. The map shows projected changes in average annualground level ozone pollution concentration in 2050 as compared to 2001, using a mid-range emissions scenario (A1B, which assumes gradual reductions from current emissions trends beginning around mid-century). (Figure source: adapted from Tagaris et al. 2009).
The climate in many parts of the Southeast and Caribbean is suitable for mosquitoes carrying malaria and yellow and dengue fevers. The small island states in the Caribbean already have a high health burden from climate-sensitive disease, including vector-borne and zoonotic (animal to human) diseases. It is still uncertain how regional climate changes will affect vector-borne and zoonotic disease transmissions. While higher temperatures are likely to shorten both development and incubation time, vectors (like disease-carrying insects) also need the right conditions for breeding (water), for dispersal (vegetation and humidity), and access to susceptible vertebrate hosts to complete the disease transmission cycle. While these transmission cycles are complex, increasing temperatures have the potential to result in an expanded region with more favorable conditions for transmission of these diseases.
Climate change is expected to increase harmful algal blooms and several disease-causing agents in inland and coastal waters, which were not previously problems in the region. For instance, higher sea surface temperatures are associated with higher rates of ciguatera fish poisoning,, one of the most common hazards from algal blooms in the region. The algae that causes this food-borne illness is moving northward, following increasing sea surface temperatures. Certain species of bacteria (Vibrio, for example) that grow in warm coastal waters and are present in Gulf Coast shellfish can cause infections in humans. Infections are now frequently reported both earlier and later by one month than traditionally observed.
Coral reefs in the Southeast and Caribbean, as well as worldwide, are susceptible to climate change, especially warming waters and ocean acidification, whose impacts are exacerbated when coupled with other stressors, including disease, runoff, over-exploitation, and invasive species.
An expanding population and regional land-use changes have reduced land available for agriculture and forests faster in the Southeast than in any other region in the contiguous United States. Climate change is also expected to change the unwanted spread and locations of some non-native plants, which will result in new management challenges.
Heat stress adversely affects dairy and livestock production. Optimal temperatures for milk production are between 40ºF and 75ºF, and additional heat stress could shift dairy production northward. A 10% decline in livestock yield is projected across the Southeast with a 9ºF increase in temperatures (applied as an incremental uniform increase in temperature between 1990 and 2060), related mainly to warmer summers.
Summer heat stress is projected to reduce crop productivity, especially when coupled with increased drought. The 2007 drought cost the Georgia agriculture industry $339 million in crop losses, and the 2002 drought cost the agricultural industry in North Carolina $398 million. A 2.2ºF increase in temperature would likely reduce overall productivity for corn, soybeans, rice, cotton, and peanuts across the South – though rising CO2 levels could partially offset these decreases based on a crop yield simulation model. In Georgia, climate projections indicate corn yields could decline by 15% and wheat yields by 20% through 2020. In addition, many fruit crops from long-lived trees and bushes require chilling periods and may need to be replaced in a warming climate.
Adaptation for agriculture involves decisions at many scales, from infrastructure investments (like reservoirs) to management decisions (like cropping patterns). Dominant adaptation strategies include altering local planting choices to better match new climate conditions and developing heat-tolerant crop varieties and breeds of livestock. Most critical for effective adaptation is the delivery of climate risk information to decision-makers at appropriate temporal and spatial scales, and a focus on cropping systems that increase water-use efficiency, shifts toward irrigation, and more precise control of irrigation delivery.
The southeastern U.S. (data include Texas and Oklahoma, not Puerto Rico) leads the nation in number of wildfires, averaging 45,000 fires per year, and this number continues to increase., Increasing temperatures contribute to increased fire frequency, intensity, and size, though at some level of fire frequency, increased fire frequency would lead to decreased fire intensity. Lightning is a frequent initiator of wildfires, and the Southeast currently has the greatest frequency of lightning strikes of any region of the country. Increasing temperatures and changing atmospheric patterns may affect the number of lightning strikes in the Southeast, which could influence air quality, direct injury, and wildfires. Drought often correlates with large wildfire events, as seen with the Okeefenokee (2007) and Florida fires (1998). The 1998 Florida fires led to losses of more than $600 million. Wildfires also affect human health through reduced air quality and direct injuries. Expanding population and associated land-use fragmentation will limit the application of prescribed burning, a useful adaptive strategy. Growth management could enhance the ability to pursue future adaptive management of forest fuels.
Forest disturbances caused by insects and pathogens are altered by climate changes due to factors such as increased tree stress, shifting phenology, and altered insect and pathogen lifecycles. Current knowledge provides limited insights into specific impacts on epidemics, associated tree growth and mortality, and economic loss in the Southeast, though the overall extent and virulence of some insects and pathogens have been on the rise (for example, Hemlock Woolly Adelgid in the Southern Appalachians), while recent declines in southern pine beetle (Dendroctonus frontalis Zimmerman) epidemics in Louisiana and East Texas have been attributed to rising temperatures. Due to southern forests’ vast size and the high cost of management options, adaptation strategies are limited, except through post-epidemic management responses – for example, sanitation cuts and species replacement.
The Southeast has the existing power plant capacity to produce 32% of the nation’s electricity. Energy use is approximately 27% of the U.S. total, more than any other region. Net energy demand is projected to increase, largely due to higher temperatures and increased use of air conditioning. This will potentially stress electricity generating capacity, distribution infrastructure, and energy costs. Energy costs are of particular concern for lower income households, the elderly, and other vulnerable communities, such as native tribes. Long periods of extreme heat could also damage roadways by softening asphalt and cause deformities of railroad tracks, bridge joints, and other transportation infrastructure.
Increasing temperatures will affect many facets of life in the Southeast and Caribbean region. For each impact there could be many possible responses. Many adaptation responses are described in other chapters in this document.
Source: http://nca2014.globalchange.gov/report/regions/southeast
. - Water Availability
Water Availability
Water resources in the Southeast are abundant and support heavily populated urban areas, rural communities, unique ecosystems, and economies based on agriculture, energy, and tourism. The region also experiences extensive droughts, such as the 2007 drought in Atlanta, Georgia, that created water conflicts among three states. In northwestern Puerto Rico, water was rationed for more than 200,000 people during the winter and spring of 1997-1998 because of low reservoir levels. Droughts are one of the most frequent climate hazards in the Caribbean, resulting in economic losses. Water supply and demand in the Southeast and Caribbean are influenced by many changing factors, including climate (for example, temperature increases that contribute to increased transpiration from plants and evaporation from soils and water bodies), population, and land use. While change in projected precipitation for this region has high uncertainty, there is still a reasonable expectation that there will be reduced water availability due to the increased evaporative losses resulting from rising temperatures alone.
With projected increases in population, the conversion of rural areas, forestlands, and wetlands into residential, commercial, industrial, and agricultural zones is expected to intensify. The continued development of urbanized areas will increase water demand, exacerbate saltwater intrusion into freshwater aquifers, and threaten environmentally sensitive wetlands bordering urban areas.
Additionally, higher sea levels will accelerate saltwater intrusion into freshwater supplies from rivers, streams, and groundwater sources near the coast. The region’s aquaculture industry also may be compromised by climate-related stresses on groundwater quality and quantity. Porous aquifers in some areas make them particularly vulnerable to saltwater intrusion. For example, officials in the city of Hallandale Beach, Florida, have already abandoned six of their eight drinking water wells.
With increasing demand for food and rising food prices, irrigated agriculture will expand in some states. Also, population expansion in the region is expected to increase domestic water demand. Such increases in water demand by the energy, agricultural, and urban sectors will increase the competition for water, particularly in situations where environmental water needs conflict with other uses.
Left: Projected trend in Southeast-wide annual water yield (equivalent to water availability) due to climate change. The green area represents the range in predicted water yield from four climate model projections based on the A1B and B2 emissions scenarios. Right: Spatial pattern of change in water yield for 2010-2060 (decadal trend relative to 2010). The hatched areas are those where the predicted negative trend in water availability associated with the range of climate scenarios is statistically significant (with 95% confidence). As shown on the map, the western part of the Southeast region is expected to see the largest reductions in water availability. (Figure source: adapted from Sun et al. 201384).
As seen from Figure 17.11, the net water supply availability in the Southeast is expected to decline over the next several decades, particularly in the western part of the region. Analysis of current and future water resources in the Caribbean shows many of the small islands would be exposed to severe water stress under all climate change scenarios.Figure 17.12: A Southeast River Basin Under Stress
The Apalachicola-Chattahoochee-Flint River Basin in Georgia exemplifies a place where many water uses are in conflict, and future climate change is expected to exacerbate this conflict. The basin drains 19,600 square miles in three states and supplies water for multiple, often competing, uses, including irrigation, drinking water and other municipal uses, power plant cooling, navigation, hydropower, recreation, and ecosystems. Under future climate change, this basin is likely to experience more severe water supply shortages, more frequent emptying of reservoirs, violation of environmental flow requirements (with possible impacts to fisheries at the mouth of the Apalachicola), less energy generation, and more competition for remaining water. Adaptation options include changes in reservoir storage and release procedures and possible phased expansion of reservoir capacity. Additional adaptation options could include water conservation and demand management. (Figure source: Georgakakos et al. 20105).New freshwater well fields may have to be established inland to replenish water supply lost from existing wells closer to the ocean once they are compromised by saltwater intrusion. Programs to increase water-use efficiency, reuse of wastewater, and water storage capacity are options that can help alleviate water supply stress.
The Southeast and Caribbean, which has a disproportionate number of the fastest-growing metropolitan areas in the country and important economic sectors located in low-lying coastal areas, is particularly vulnerable to some of the expected impacts of climate change. The most severe and widespread impacts are likely to be associated with sea level rise and changes in temperature and precipitation, which ultimately affect water availability. Changes in land use and land cover, more rapid in the Southeast and Caribbean than most other areas of the country, often interact with and serve to amplify the effects of climate change on regional ecosystems.
Source: http://nca2014.globalchange.gov/report/regions/southeast
.
.
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
Temperature Increases Across the U.S.
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 Sixteen Hottest Years on Record
The chart above shows the global combined land and ocean temperature rank and how much the average temperature for that year departed from the average temperature for the period from 1880 to 2015. Note that of the 16 hottest years on record for that period have occurred in the last 17 years. 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. Mount Rainier’s glaciers are an example. The mountain's glaciers are the largest single-mountain glacier system in the contiguous 48 states. They represent 25% of the total ice area in the contiguous 48 states and contain as much ice (by volume) as all the other Cascade volcanoes combined. However, these glaciers shrank 22% by area and 25% by volume between 1913 and 1994 due to global warming. In the Great Lakes, 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 sea level rise will affect coast of the Southeast
For a good summary of climate change impacts on global sea level rise, visit the National Climate Assessment
The Southeast Coastline: Savannah, Georgia
See how rising sea levels will affect Georgia's coast under different global warming conditions. Be patient, the visualization tool can take a few minutes to load, depending on your internet connection.
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
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.
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.
Runoff patterns are shifting in many parts of the world with more rain and less snow falling as precipitation.
Source: Changing Climate, Changing Forests: Th e Impacts of Climate Change on Forests of the Northeastern United States and Eastern Canada
Climate Change in the Southeast: Temperature and Precipitation
Temperature: Projected Change
Climate change is causing increases in temperature across the Southeast. Since 1970, average annual temperatures in the region have increased by about 2°F, with the greatest warming occurring during the summer. Temperatures are projected to increase by 4°F to 8°F by the end of the century. There are also more predicted days over 95°F and fewer predicted freezing events. Across the Southeast, temperatures will vary somewhat over space and time. Inland areas are projected to warm more than coasts. Natural cycles, including the El Niño Southern Oscillation, tropical weather systems, and differences in atmospheric pressure across key regions of the Earth, are anticipated to drive short-term temperature fluctuations.
Precipitation: Projected Changes
Heavy downpours have also increased in the Southeast. There has also been a substantial increase in the intensity, frequency, duration, and strength of Atlantic hurricane activity since the 1980s, and further increases are projected. However, in addition to some very wet periods, the region has also experienced periods of extreme drying. Projecting future precipitation for the Southeast is challenging because the region lies in the transition between an increasingly wet northern region and a drying southwest. Areas in southwestern portion of the Southeast region may experience drier conditions, while the northeastern areas may experience wetter conditions, with natural variability having a strong influence on patterns across the entire region.
Good summaries of impacts on freshwater can be found in the National Climate Assessment
High Streamflow is Increasing, Raising Flood Risks
High Streamflow is Increasing, Raising Flood Risks
By Climate Central
With the frequency of heavy precipitation increasing across most of the U.S., it follows that streamflow levels may be increasing as well. A Climate Central analysis of streamflow data at more than 2,100 active gauges found that the number of days with high stream flow (the top 25 percent of readings) has risen over the past 30 years in the largest rivers of the U.S., including the Ohio, Missouri, and Mississippi. This streamflow analysis complements the National Climate Assessment and previous Climate Central analyses, which show that heavy precipitation is increasing in the Northeast and Midwest, consistent with what is expected in a warming world. Heavy precipitation is the key element driving streamflow, although urbanization and the reduction of permeable surfaces also play roles, as does the engineering of dams and levees. The increasing number of days with high streamflow indicates that the risk for stream and river flooding is also on the rise. Additional data from the National Climate Assessment shows this is already happening, as the magnitude of flooding is increasing in the Mississippi Valley, Ohio Valley, and the Northeast. With the recent flooding in the Mississippi Valley, we examined the streamflow data for additional seasonal trends. In addition to heavy rain, spring snow melt can also play a role in streamflow. During the spring, we found some of largest increases in high streamflow days in Upper Mississippi River Valley and the Northwest.
More Snowfall Records, More Recently
As the world warms, the overall area of North America covered by snow is decreasing. One reason is that an increasing percentage of winter precipitation is falling as rain instead of snow in many locations. A Climate Central report found that between sea level and 5,000 feet in elevation, a smaller percentage of winter precipitation is falling as snow in the western U.S. The subsequent decline in snowpack affects reservoir levels and irrigation, as the melting snow provides water for the Westin the dry summer months.
However, the relationship is more complex at the local level. Rising temperatures can cause some individual storms to produce more snow. That’s because for every 1°F rise in temperature, the atmosphere can hold 4 percent more water. This, in turn, means more water is available to fall as snow or rain.
In the Great Lakes region, warming is leading to more snow in some of the downstream areas. When the lakes go longer without forming ice, that allows for increased evaporation, and the potential for more lake-effect snow.
Nationwide, more than 40 percent of counties have had their biggest 2-day snow totals since 1980. Our analysis excluded counties where the 2-day snowfall record was less than 3 inches. So even if the average amount of snow at the local level may be trending down, the snow that falls may come in larger batches. This is notable in the northeastern cities, where the biggest storms are usually nor’easters, which tap into the Atlantic Ocean for moisture. As the Washington Post’s Capital Weather Gang has pointed out:Seven of Washington, D.C.’s top 10 snowstorms since 1889 have occurred since 1979.All five of Philadelphia’s highest snowfalls have occurred since 1983. Its top three have happened since 1996.In New York City, seven of the nine biggest snows have occurred since 1996. Three of the top five have come in the past decade.Eight of Boston’s top 10 snowstorms have come since 1978. Half have occurred since 2003.
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.
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:
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, 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 the Northeast by clicking on the topics below
Impacts on Southeast Ecosystems
Source:https://19january2017snapshot.epa.gov/climate-impacts/climate-impacts-southeast_.html
Warmer air and water temperatures, hurricanes, increased storm surges, and sea level rise are expected to alter the Southeast's local ecosystems and agricultural productivity.
Warmer temperatures could increase the number and intensity of wildfires, as well as outbreaks of damaging forest pests, including the hemlock woolly adelgid. Declining freshwater availability, saltwater intrusion, land loss, drought, and increasing temperatures are expected to stress agricultural crops and decrease yields. Some croplands may be lost entirely to inundation this century while production of crops that need chilling periods, such as many fruits, may need to shift northward with warming temperatures. High temperatures also cause heat stress for dairy cows and livestock and reduce production yields, potentially leading to relocation of these industries, or shifts to more heat-tolerant breeds.
Sea level rise will increase the salinity of estuaries, coastal wetlands, tidal rivers, and swamps. Rapid sea level rise could also eliminate some barrier islands that currently protect inland habitats, while reduction of wetlands increases the potential for loss of important fishery habitat. Ocean warming could affect seafood harvest in the Southeast by changing the species in the region, altering migration patterns and timing of fish presence, or affecting fish growth rates.
Aquatic Ecosystems and Fish
Adapted from: https://www.fs.usda.gov/ccrc/topics/aquatic-ecosystems
Although warmwater fishes are not expected to face the nearly-universal declines predicted for coldwater fishes, many warmwater species face risks of local extinctions, and some face global extinction, if climate change unfolds as predicted. As temperatures increase, some warmwater species (native and non-native) will invade more area, and indeed already have, but many others will fare worse. The latter group includes, among others, animals with:
Aquatic invertebrates with high dispersal rates (for example, insects), may be able to shift distributions to keep pace with climate changes, but dispersal abilities of many others (such as mussels, snails, crayfish, and groundwater-restricted species) preclude migration as a viable strategy for survival. Habitat loss for warmwater fishes is predicted to be greatest in the southern regions of the U.S., whereas suitable habitats may increase in northern areas for some species, particularly widely distributed, habitat generalists such as smallmouth bass.
A number of warmwater fishes and invertebrates have small native ranges (sometimes reproducing only in one to several springs), while many others have highly fragmented distributions. Narrowly distributed species have little resilience for withstanding extreme events. One severe drought that dries several springs may eliminate a species. Drought dramatically reduced sizes of some isolated mussel populations in the southeastern U.S., possibly to densities too low to allow for successful reproduction, and river fragmentation by reservoirs prevents recolonization.
Losses in warmwater fauna have occurred already, due to human modifications or climate, and are expected to intensify. Population extirpations presumably due to impoundments include 38 snail species in the Mobile River and 49 mussel species in the Tennessee River, numbers that will increase if climatic changes spur another era of extensive dam construction in the southeastern U.S.
Plant Communities
Adapted from: https://19january2017snapshot.epa.gov/climate-impacts/climate-impacts-northeast_.html#Ecosystems
For a good summaries of climate change impacts on tribes, the Northeast, 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
Coastal Everglades, deprived of fresh water, near unhealthy ‘tipping point’
Everglades Foundation wetland ecologist, Dr. Stephen Davis, explains the importance of the restoration of the Everglades natural flow and its importance. Carl Juste cjuste@miamiherald.com
BY JENNY STALETOVICH
SHARK RIVER
At the bottom of the Everglades along the mouth of the Shark River, a towering mangrove forest stands in a place few people outside anglers and researchers ever see: at the edge of a vast shallow bay where the salty sea and freshwater marshes conspired to erect a cathedral of trees.
In the current fight over restoration, this isolated region often gets overlooked. While Lake Okeechobee pollution to the north grabs headlines and gets the attention of Florida lawmakers, it’s actually here where damage may be most profound.
For the last 16 years, nearly 80 scientists and their students from 29 organizations — including all the state’s major universities, the National Park Service and the South Florida Water Management District — have embarked on one of the longest and largest studies ever conducted on South Florida’s coastal Everglades. They now fear the system may be at what lead investigator Evelyn Gaiser calls a “tipping point,” where change is happening faster than scientists expected and spinning into a self-perpetuating cycle of decline.
The mangroves ringing the coast are moving inland, overtaking vital freshwater marshes. Growing swathes of peat, the rich mucky soil that formed over a few thousand years, are collapsing. And periphyton, the spongy brown mats of native algae that form the foundation of the food chain, is shrinking.
WE HAVE THESE TIPPING POINTS, RIGHT? AND WHEN YOU’RE ON THE EDGE OF A MAJOR STATE CHANGE THAT SEEMS IRREVERSIBLE, CALLING ATTENTION TO THIS PROBLEM AND DOING WHATEVER WE CAN TO REMEDIATE (OR FIX) IT IS REALLY IMPORTANT.
Evelyn Gaiser, lead investigator and Florida International University aquatic ecologist
Aside from losing one of the planet’s rarest ecosystems, changes happening in the system could also have global consequences, damaging one of the region’s main defenses against climate change fueled by greenhouse gases.
“The threat here is we’re changing the system from one that is very good at sucking carbon dioxide out of the atmosphere,” said Gaiser, a Florida International University aquatic ecologist, “to one that’s very rapidly losing it.”
Two forces are likely driving the change in the southern Glades: decades of flood control that altered historic water flow and rising sea levels. Both cause different problems, but can be partly solved in the short-term with a fairly straight-forward solution: more freshwater flowing south.
“The pace at which we accelerate freshwater restoration is going to matter to the future of being able to do anything with restoration,” Gaiser said.
The research effort now includes dissecting the entire ecosystem to look for signs of trouble, but it started with the long-running battle over setting phosphorus pollution levels in the Everglades. The nutrient, a primary ingredient in fertilizer, is blamed for the pollution in Lake Okeechobee that this past year stained both coasts and left the Treasure Coast coated with toxic algae.
In 1997, Gaiser was a post-doc student hired to help a team of scientists led by Ron Jones, a then-little known FIU microbiologist who discovered that the marshes could not withstand phosphorus at levels above 10 parts per billion. That amount is an incredibly low threshold that remains the bane of farmers who for decades relied on phosphorus-rich fertilizer to enhance crops — including a half million acres of sugarcane fields.
Lake Okeechobee, which once supplied a steady flow of clean water to the marshes, also has phosphorous concentrations too high for the system, thanks to now prohibited back-pumping from the sugar fields and runoff from suburbs, pastures and farms to its north. When the lake gets too full, much of that water is now sent down the Caloosahatchee and St. Lucie Rivers to the west and east, where it has repeatedly triggered stinky algae blooms that kill fish.
To help pin down the delicate balance of phosphorous in the Glades, Gaiser spent nearly every day in the field over five years, monitoring 325-foot long plastic and Styrofoam flumes built in the marshes.
When the the study ended in 2000, researchers realized they had another question to answer: if the marshes thrived on such a tiny amount of phosphorus, then what was fueling such an enormous mangrove forest along the coast of the Everglades — an ecosystem that rivals the Amazon in its ability to recycle and maintain itself in healthy conditions. It turns out the forest is the start of one of the planet’s rarest phenomenons: an upside down estuary. In a healthy Everglades, the phosphorus in the ocean fuels the mangrove growth, so as the saltwater turns brackish and then fresh, the mangrove trees themselves shrink and give way to the sweeping marshes that once dominated much of the Everglades.
As rising sea levels push deeper up creeks and rivers and freshwater flow from the north slows, the marshes that once made up much of the southern Glades have collapsed — at increasing speed.
Because those coastal marshes were so vulnerable, scientists also realized they cried for ongoing monitoring, so they applied to include the Everglades in the National Science Foundation’s Long Term Ecological Research Program. Gaiser said they never expected to be accepted. The highly competitive network has included only 25 such sights across the planet in its 37-year history.
| 25 | |
| The coastal Everglades project is one of just 25 sights around the planet included in the National Science Foundation’s Long Term Ecological Research network. | |
So many studies occur in the Everglades it can be hard to keep track. But the Everglades LTE stands out because the enormity of its scale matches the pace of research with the pace of change.
The research findings could also stand as a bulwark against shifting politics that might disregard science. In the current debate over building a giant reservoir south of the lake, for instance, farmers, Big Sugar, and politicians have focused on whether and how much a reservoir will help stem the flow of polluted lake water in he Caloosahatchee and St. Lucie rivers. Critics call it a bad solution based on faulty science that will kill agriculture jobs.
But the LTE research shows that failure to get more water flowing south could strangle the southern Glades, continuing the decline of fresh water marshes and too-salty Florida Bay, which also has been hammered by seagrass-killing algae blooms.
The impact on Everglades peat has already been profound. Peat is a wetlands version of soil, the muck created in the soggy marshes that supports its unique plants. It needs to stay submerged to accumulate, but too much saltwater can cause it to collapse. In the 1990s, University of Miami professor Hal Wanless noticed large areas of peat were beginning to collapse. When the LTE began looking into it, they realized the pace was much faster than expected.
“You can see them from satellite imagery,” Gaiser said. “There are areas many square meters wide if not bigger.”
At first, they suspected the collapse was a normal process, the reason big, open water lakes suddenly appear in the Everglades, she said.
They now fear the collapse is accelerating at a faster rate as sea water inches inland, threatening to turn much larger areas into big expanses of dark open water.
ONCE YOU LOSE THAT SOIL, IT’S GONE. YOU CREATE A PLACE WHERE NOTHING CAN EFFECTIVELY GROW. WE’RE NOT EVEN SURE MANGROVES CAN GROW THERE.
Evelyn Gaiser, lead investigator and Florida International University aquatic ecologist
“Once you lose that soil, it’s gone,” she said. “You create a place where nothing can effectively grow. We’re not even sure mangroves can grow there.”
Further up the system, the team has also documented the disappearance of periphyton mats that over thousands of years have survived in an environment with hardly any phosphorus. It was here that scientists first realized how sensitive the Everglades are. When they started measuring phosphorus, they looked at what was in the water. But the FIU scientists led by Jones figured out that the true measure was in the periphyton, which soaked up what little was in the water.
“You could take a water sample and it doesn’t show anything,” she said. Meanwhile “the whole community is changing.”
While between 700 and 800 different kinds of algae exist in the wider Everglades, the periphyton mats contain just 10 to 15 hardy enough to survive the harsh conditions. The balance between the diatoms — the single-celled algae — that are among the oldest living things on the planet and the bacteria and other micro-organisms inhabiting the mats is so sensitive, that the tiniest amount of nutrient can make a difference.
In one of Gaiser’s projects, scientists are literally tracking a single molecule of water as it moves down the system, measuring how it changes when hammered by the forces of man and nature.
“They are the backbone of the Everglades ecosystem,” she said. “They also engineer the chemistry and even sometimes the physics and gas exchange of the water because they are full of these little microorganisms that are depending on phosphorus for growth.”
With too much phosphorus, bacteria in the algae mats seize control, consuming them from the inside out. In the place of the periphyton, other things can move in and dominate — for instance, expanses of less biologically diverse cattails that grow in the most phosphorus-tainted boundaries of the Everglades.
A CATTAIL LIVES ANYWHERE IN THE WORLD. SAME THING HAPPENS IN THE LITTLE MICROBIAL COMMUNITY. WEEDY THINGS COME IN THAT YOU COULD FIND IN ANY LAKE OR RESERVOIR.
Evelyn Gaiser, lead investigator and Florida International University aquatic ecologist
“A cattail lives anywhere in the world. Same thing happens in the little microbial community,” Gaiser said. “Weedy things come in that you could find in any lake or reservoir.”
What researchers haven’t been able to nail down yet is exactly how much this happened in the past.
Core samples taken in Florida Bay and the mangrove forests provide a record they think reflects what happens in certain conditions. But they haven’t been able to get samples in the places most likely to provide answers now: the upper Everglades where soils are badly preserved or shallow lakes where soils are constantly stirred up.
What they do know is the Everglades needs more water, from Biscayne Bay to the east — where a coastal restoration project slated for 2021 will clear the way for more water even if no reservoir exists to provide it — to Florida Bay.
In the next six-year phase of research, they’re also hoping to solve another riddle: projecting the “differential vulnerabilities” of the Everglades various parts to determine which are in most urgent need of fixing.
“It is amazing how just a couple of parts per thousand of salinity can really affect a sawgrass marsh,” Gaiser said. “With the phosphorus, we know any extra molecule has an effect.”
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
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 for Tribes
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
Listen to how climate change is affecting the traditional food of Southeast tribes
Click the button below to learn what the National Climate Assessment says about the Southeast
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.