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A presentation developed by the National Academy of Sciences based on its report Ecological Impacts of Climate Change (2009): www.nas.edu/climatechange. National Academy of Sciences National Academy of Engineering Institute of Medicine National Research Council
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The Climate is Changing Temperatures are rising Sea levels are rising The ocean is acidifying Climate change is reflected in water cycle changes and in extreme weather Temperature rise, indicated by color (red=higher rate of increase). Earth’s surface temperature has risen ~1.3˚ F since 1850. Image courtesy of the Joint Institute for the Study of the Atmosphere & Ocean, U. of Washington. National Academy of Sciences National Academy of Engineering Institute of Medicine National Research Council
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Ecological Impacts Living things are intimately connected to their physical surroundings. Ecosystems are affected by changes in: –temperature –rainfall/moisture –pH – salinity (saltiness) – activities & distribution of other species – …many other factors National Academy of Sciences National Academy of Engineering Institute of Medicine National Research Council
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Ecological Impacts As a result of climate change, species and ecosystems are experiencing changes in: –ranges –timing of biological activity –growth rates –relative abundance of species – cycling of water and nutrients – the risk of disturbance from fire, insects, and invasive species National Academy of Sciences National Academy of Engineering Institute of Medicine National Research Council
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Ecological Impacts As a result of climate change, species and ecosystems are experiencing changes in: –ranges –timing of biological activity –growth rates –relative abundance of species – cycling of water and nutrients – the risk of disturbance from fire, insects, and invasive species National Academy of Sciences National Academy of Engineering Institute of Medicine National Research Council
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Range Shifts Species are relocating to areas with more tolerable climate conditions. Range shifts particularly threaten species that: –cannot move fast enough –depend on conditions that are becoming more rare (like sea ice) Plant hardiness zone maps, 1990 and 2006. Most zones shifted northward in this period. Map courtesy of the National Arbor Day Foundation. National Academy of Sciences National Academy of Engineering Institute of Medicine National Research Council
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Ecological Impacts As a result of climate change, species and ecosystems are experiencing changes in: –ranges –timing of biological activity –growth rates –relative abundance of species – cycling of water and nutrients – the risk of disturbance from fire, insects, and invasive species National Academy of Sciences National Academy of Engineering Institute of Medicine National Research Council
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Timing of Biological Activity Some seasonal biological activities are happening 15-20 days earlier than several decades ago: –Trees blooming earlier –Migrating birds arriving earlier –Butterflies emerging earlier Changes in timing differ from species to species, so ecological interactions are disrupted. European pied flycatcher chicks are now born later than the caterpillars they eat. Images used under the terms of the GNU Free Documentation License. National Academy of Sciences National Academy of Engineering Institute of Medicine National Research Council
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Global Changes, Local Impacts Although climate change is global, the ecological impacts are often local. What’s happening in your backyard? National Academy of Sciences National Academy of Engineering Institute of Medicine National Research Council
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Impacts in the Pacific Coastline Shifting Ranges of Checkerspot Butterflies Edith’s checkerspot: range has shifted northward and to higher elevations over 40+ years Quino checkerspot: first endangered species for which climate change is officially listed as a threat and as a factor in the plan for its recovery Image courtesy of Dr. Gordon Pratt, www.quinocheckerspot.com. National Academy of Sciences National Academy of Engineering Institute of Medicine National Research Council
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Impacts in the Pacific Coastline Changes in the Water Shift in species ranges: many species moving northward Mysterious dead zones along Washington and Oregon coastline: cause undetermined but potential links to climate change Scientists retrieve a water sample for research on a recurring “dead zone” off the coasts of Washington and Oregon. Image courtesy of Oregon State University. National Academy of Sciences National Academy of Engineering Institute of Medicine National Research Council
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Impacts in the Pacific Coastline California Wine Industry: Unwelcome Changes? Climate change affects managed ecosystems like vineyards and farms just as it affects natural ecosystems Future warming unlikely to help wine growers in California’s premium wine regions: some areas projected to become “marginal” by 2100 National Academy of Sciences National Academy of Engineering Institute of Medicine National Research Council
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Impacts in Alaska and the Arctic Effects on Ice-Dependent Animals Year-round sea ice shrinking: walruses and other animals challenged to find platforms for nursing and resting Polar bears facing difficult hunting conditions: seals now surfacing in open ocean instead of holes in ice National Academy of Sciences National Academy of Engineering Institute of Medicine National Research Council
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Impacts in Alaska and the Arctic Changing Food Chains Increased shrub growth presenting a threat to caribou (wild reindeer) –Shrubs crowding out lichens (a key winter food for caribou) –Shrubs collect snow, causing deep snowdrifts: deep snow makes it hard for caribou to reach lichens hidden beneath National Academy of Sciences National Academy of Engineering Institute of Medicine National Research Council
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Impacts in Alaska and the Arctic Feedback Loops: Arctic Warming Faster The Arctic is warming twice as fast as the rest of the planet –As sea ice and seasonal snow cover melts, previously reflective white surfaces converted to darker surfaces (to ocean water or vegetation) –Thawing permafrost releases carbon dioxide and methane into the atmosphere, increasing greenhouse gases Rate of warming, indicated by colors (red=higher rate). Image created with data from the Goddard Institute for Space Studies. National Academy of Sciences National Academy of Engineering Institute of Medicine National Research Council
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Impacts in Western Mountains Wildfire, Drought, and Insects: Complex Interactions Climate change increases the risk of fire in areas where decades of total fire suppression have resulted in buildup of dead fuels. Wildfire increasing in frequency, size, season length: –Longer, more intense summer droughts stressing trees –Stressed trees are more susceptible to attacking beetles, which leave standing dead fuels in their wake A wildfire in Bitterroot National Forest, Montana. Image courtesy of John McColgan, USDA Forest Service. National Academy of Sciences National Academy of Engineering Institute of Medicine National Research Council
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Impacts in Western Mountains Effects on The American Pika Climbing to higher elevations in response to warming Many populations now isolated on “mountaintop islands” Pika images courtesy of J. R. Douglass, Yellowstone National Park; Aerial image courtesy NASA. National Academy of Sciences National Academy of Engineering Institute of Medicine National Research Council
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Impacts in Western Mountains Changes in Trout Habitat Earlier springs, warmer summers reducing stream flows as mountain snow melts off earlier in the season Some streams reaching temperatures lethal to trout (>78˚F) Image courtesy USGS. National Academy of Sciences National Academy of Engineering Institute of Medicine National Research Council
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Impacts in Southwestern Deserts Wildfire and Invasive Species Nonnative grasses becoming established in deserts: –Red brome (in the Mojave) –Buffelgrass (in the Sonoran) Grasses transform desert into flammable grassland: fire-adapted grasses re-establish quickly, pushing out native species like Saguaro cactus Spread of grasses not directly a result of climate change, but warming may allow them to further spread in the desert and extend to higher elevations. Image courtesy T. Esque, USGS. National Academy of Sciences National Academy of Engineering Institute of Medicine National Research Council
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Impacts in Southwestern Deserts The Piñon Pine: Past a Tipping Point Drought in 2000-2003 stressed a large swath of piñons, leaving them susceptible to infestation by pine bark beetles This example shows how a stressful event can trigger dramatic ecological change when an ecosystem is subject to many interacting stresses 20022004 Images courtesy D. Allen, USGS. National Academy of Sciences National Academy of Engineering Institute of Medicine National Research Council
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Impacts in the Central U.S. Agricultural Impacts Difficult to pinpoint climate impacts: climate change occurring along with improvements in farming techniques In general, plants may: –Grow faster (increasing yields unless it becomes too warm or crops mature too early) –Be affected by carbon dioxide levels (increased growth for some plants, not for others) Good information about changes and adaptive practices is essential for farmers National Academy of Sciences National Academy of Engineering Institute of Medicine National Research Council
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Impacts in the Central U.S. Migratory Waterways: Drying Up? “Playa lakes” or “Prairie potholes” essential for migrating birds: used for resting, feeding, and mating Climate change, combined with other pressures (irrigation demands, pollution, etc.), may dry up these important waterways Image courtesy of the U.S. Fish and Wildlife Service. National Academy of Sciences National Academy of Engineering Institute of Medicine National Research Council
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Impacts in the Southeast Challenges to Everglades Restoration Everglades has shrunk due to human manipulation of the region’s water; ongoing efforts aim to restore the ecosystem. Climate change impacts (increasing water temperature, changes in precipitation) may make restoration efforts more difficult 1850Today Images courtesy Rodney Cammauf, National Park Service (panther); South Florida Water Management District (maps) National Academy of Sciences National Academy of Engineering Institute of Medicine National Research Council
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Impacts in the Southeast Sea-level Rise Fragments barrier islands, reconfigures shorelines May leave certain ecosystems struggling to adapt—in particular those adapted to the conditions between land and sea Landward movement of mangroves and marshes may be inhibited by human development National Academy of Sciences National Academy of Engineering Institute of Medicine National Research Council
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Impacts in the Southeast Coral Reefs: Multiple Changes Climate change is compounding other factors affecting reefs (coastal development, pollution, overfishing) Heat stress causes coral bleaching: corals expel symbiotic algae, leaving white “bones” behind (deadly to coral if long- lasting) Ocean acidification affects marine organisms’ ability to build shells and skeletons: likely to slow or stop the growth of coral by 2100 Image courtesy of NOAA. Coral bleaching National Academy of Sciences National Academy of Engineering Institute of Medicine National Research Council
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Impacts in the Southeast Northward Movement of Tropical Species Bird and butterfly watchers across the Southeast looking out for new species; some former seasonal migrants now staying year-round The rufous hummingbird has become a year- round resident in Alabama. Image courtesy Dean E. Briggins, U.S. Fish and Wildlife Service. National Academy of Sciences National Academy of Engineering Institute of Medicine National Research Council
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Impacts in the Northeast Fisheries Cod: affected by water temperature –Habitat may become restricted to cooler pockets (<54˚F for adults, <46˚F for young) Lobsters: affected by oxygen levels –Warmer water holds less oxygen: oxygen becomes insufficient for lobsters >79˚F –In north, warming may improve lobster habitat Oysters: Deadly parasite Perkinsus marinus moving northward –Range expanded from Chesapeake Bay to Maine: shift linked to above-average winter temperatures National Academy of Sciences National Academy of Engineering Institute of Medicine National Research Council
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The Role of Human Beings Causes of Climate Change It is very likely that most of the climate change in the current era is the result of human activities. –Human activities have increased concentrations of greenhouse gases in the atmosphere. –These gases trap heat and cause the Earth to warm. Figure adapted from Climate Change 2007: The Physical Science Basis. Working Group 1 Contribution to the 4th Assessment Report of the Intergovernmental Panel on Climate Change. Figure SPM.5. Cambridge University Press. National Academy of Sciences National Academy of Engineering Institute of Medicine National Research Council
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The Role of Human Beings Rate of Climate Change Climate change in the current era is expected to be extremely rapid compared to transitions in and out of past ice ages. Ecosystems are more vulnerable to changes that happen rapidly. A scientist holding an ice core—a sample taken from polar ice caps or mountain glaciers. Ice cores reveal clues about climate changes in Earth’s past. Image courtesy USGS National Ice Core Laboratory. National Academy of Sciences National Academy of Engineering Institute of Medicine National Research Council
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The Role of Human Beings Compounding Factors Human activities have many other effects on ecosystems. These effects compound the effects of climate change, making it more difficult for ecosystems to adapt. –Pollution –Habitat fragmentation –Invasive species – Overfishing – Manipulation of water sources – …and much more National Academy of Sciences National Academy of Engineering Institute of Medicine National Research Council
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