Major Changes Ahead Due to Global Warming, Says New Federal Report

Mid-Atlantic Region May Be Particularly Vulnerable

WASHINGTON (June 12, 2000) - The first comprehensive assessment of global warming's potential impact on the United States warns that some U.S. ecosystems are likely to disappear entirely as a result of climate change. The 145-page overview, "Climate Change Impacts on the United States," was released today for public comment by the U.S. Global Change Research Program.

Researchers at Pennsylvania State University released a companion overview on the Mid-Atlantic region earlier this year that details the potential harm caused by rising temperatures and sea levels on an area stretching from southeastern New York state to North Carolina. The Mid-Atlantic Regional Assessment overview report is available on the Web at

"The Mid-Atlantic assessment shows that many of the region's distinct natural features could deteriorate as a result of changing climate," says Susan Subak, a senior research associate at the Natural Resources Defense Council. "Whether we're talking about Chesapeake Bay fisheries and recreational areas or Southern Appalachian forest and bird habitats, rising temperatures would put further stress on natural systems in this populous region. Cutting our consumption of fossil fuels, particularly from vehicles and electricity, would limit the increase of heat-trapping gases in the atmosphere, and help prevent the worst-case scenarios."

The national assessment evaluates global warming's potential impact on 20 geographic areas and five sectors: agriculture, coastal areas, forests, human health and water resources. The draft report's main findings include:

  • Continued growth in worldwide emissions is likely to increase average temperatures across the United States by 5-10 degrees Fahrenheit by 2100.

  • Some ecosystems, such as alpine meadows in the Rocky Mountains and some barrier islands, are likely to disappear entirely, while others, such as forests of the Southeast, are likely to experience major species shifts or break up.
  • Drought is an important concern in every region and many regions are at risk from increased flooding and water quality problems. Snowpack changes are especially important in the West, Pacific Northwest, and Alaska.
  • Climate change and the resulting rise in sea level are likely to exacerbate threats to buildings, roads, powerlines, and other infrastructure in climatically sensitive places, such as low-lying coastlines.
  • Climate change will very likely magnify the cumulative impacts of other stresses, such as air and water pollution and habitat destruction. For some systems, such as coral reefs, the effects are very likely to exceed a critical threshold, bringing irreversible damage.
  • Heat stress from higher summer temperatures, more frequent and extensive flooding, and extended ranges of disease-bearing insects may increase the risk of illness and pose additional challenges to the public health care system.

Some adverse impacts will be unavoidable because heat-trapping gases are long-lasting in the atmosphere, and because emissions already have changed our climate. These impacts will be aggravated by other stresses on the environment and by changing socioeconomic conditions.

The national assessment offers Americans suggestions on preparing for global warming. One of the most important is to limit the impact of development on the environment, especially in areas vulnerable to species and habitat loss. By reducing these stresses, we can support the capacity of natural ecosystems and communities to respond to a changing climate.

More than 250 scientists assisted in the national assessment, and countless other experts and stakeholders contributed to the workshops and to the technical review of the documents. There will be a 60-day public comment period after the report is released.

The Natural Resources Defense Council is a national, non-profit organization of scientists, lawyers and environmental specialists dedicated to protecting public health and the environment. Founded in 1970, NRDC has more than 400,000 members nationwide, served from offices in New York, Washington, Los Angeles and San Francisco.