The Pew Center: Climate Change Could Cause Major Changes in U.S. Ecosystems

Pew Center on Climate Change-commissioned study sees trouble ahead for ecosystems caused by global warming.

Published: 13-Dec-2000

Washington, Dec. 13 /PRNewswire/ -- Global climate change will cause major changes in natural ecosystems -- and the plants and animal communities that make up these ecosystems -- across the United States, according to a report released today by the Pew Center on Global Climate Change.

The report describes the very real possibility that global warming will disrupt the integrity of many of the terrestrial ecosystems on which we depend -- ecosystems that provide humans such valuable goods and services as foods, raw materials, recreational opportunities, clean air and water, and erosion control. The importance of ecosystems extends beyond economics and tangible benefits, with many people placing a high value on the spiritual and aesthetic role nature plays in their lives. Despite the crucial roles of terrestrial ecosystems, they are increasingly threatened by the impacts of a growing human population, through habitat destruction and air and water pollution, and now as a result of global climate change.

"This report describes how climate change is likely to profoundly alter the natural environment," said Pew Center President Eileen Claussen. "It underscores the point that domestic and international action to deal with climate change is needed sooner rather than later."

The report was commissioned by the Pew Center and written by two ecologists, Dr. Jay R. Malcolm of the University of Toronto and Dr. Louis F. Pitelka of the University of Maryland Center for Environmental Science. Among the authors' conclusions:

       *  As the earth warms, the distribution of terrestrial ecosystems will          change as plants and animals follow the shifting climate.  For          example, the eastern United States will likely lose many of its          deciduous forests as climate zones shift northward.  Thus, sugar          maples, so much a part of northeastern states such as Vermont, are          likely to be replaced by oaks.  Likewise, some habitats -- such as          those found in the high elevations in mountainous regions of the West           -- are likely to shrink in a warming world.         *  Both the amount and rate of anticipated warming pose threats to the          nation's biological diversity.  The rate of anticipated climate change          is estimated to be ten times that seen in the last Ice Age.  As a          result, certain species may face dwindling numbers and even extinction          if they are unable to migrate fast enough to keep up with the changing          climate.         *  Climate change is likely to alter the quantity and quality of the          various goods and services that ecosystems provide.  For example,          climate change is likely to affect the ability of ecosystems to filter          air and water pollutants and to control soil erosion.         *  Modeling studies estimate that the productivity of plants could change          little or could increase substantially.  However, these productivity          changes will not be uniform and some regions could see declines.          While productivity may rise, so could decomposition and, with it, the          release of carbon to the atmosphere.         *  The effects of climate change on ecosystems must be considered in the          context of a range of human-caused impacts on ecosystems.  Overall,          the new threat of climate change is likely to be especially damaging          for ecological communities and species that have suffered the greatest          disruption from human development.  Natural ecosystems already under          stress because of air and water pollution will have diminished          capacity to adapt to climate change.  Likewise, habitat destruction          and fragmentation will lessen the chances that species will          successfully migrate to more suitable climates and habitats.         *  It is important to remember that ecosystems are inherently complex,          and our ability to predict how ecosystems will respond to climate          change is limited.  This uncertainty will limit our ability to          anticipate and minimize the effects of climate change on ecosystems.          In order to maximize nature's own capacity to adapt, government          officials and community leaders should continue to support efforts to          conserve biodiversity and protect natural systems.  

A complete copy of this report and other Pew Center reports can be accessed from the Pew Center's web site, .

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