On Monday, June 12, the federal government released a "Public Review Draft" of Climate Change Impacts on the United States (1). The report contains peer-reviewed information that should be of interest to the general public and certainly will make excellent summer reading for those of us who teach chemistry or other sciences.

The U.S. Global Change Research Project (USGCRP), was initiated in 1990 by the U.S. Congress to provide lawmakers with information about negative and positive impacts of global warming. In 1997, USGCRP began the National Assessment of the Potential Consequences of Climate Variability and Change. Five teams, each consisting of experts from government, industry, and academic and public organizations, used sophisticated computer models to analyze regional impacts of climate change and prepare a national synthesis of existing information. They forecast significant changes during the 21st century, including an increase in temperature in the U.S. of 3-6 °C. (This is similar to the difference in temperature between the present and the last ice age.) Many regions of the country are likely to become more like the regions immediately to their south. For example, the climate in New York City is predicted to become more like the 20th-century climate of Atlanta, and Atlanta more like Houston.

Other predicted changes are

• thawing of permafrost in Alaska, resulting in damage to roads, buildings, and forests
• increased timber harvests and inventories as a result of higher temperatures and more atmospheric CO₂
• losses of biodiversity and increased pressure from invasive, non-native species
• rises in sea level, losses of barrier beaches and islands, and increased damage from storm surges
• lowered water levels in the Great Lakes due to increased evaporation from higher-temperature water, but longer shipping seasons due to less winter icing
• more frequent and more intense droughts and downpours, increasing risks of flash floods
• rising crop yields and falling prices for agricultural commodities

The study also predicts different effects on different regions crop yields are predicted to increase in the northern plains states, but they may decrease in southern states. Even though crop yields are expected to increase a little nationwide, there may be large decreases or increases in yields of specific crops and/or in specific regions. Finally, there will almost certainly be changes that no one has yet anticipated.

The report consists of a 145-page Overview and a far longer Foundation document that contains the data and references to support the Overview. Both documents have undergone extensive technical review, first by a group of 300 experts and then by a smaller group of experts as well as participants in regional workshops that involved the public and representatives from industrial and public-interest groups. According to the report, there was a "unique level of stakeholder involvement". The views of scientists and nonscientists who had interest and expertise or who wanted to lobby for changes in the report were heard and considered. As part of this process the current draft is available for 60 days for public comment (June 12-August 11), after which it will be revised and forwarded to the President, the Congress, and federal agencies.

Given the purpose of the study, it is surprising that the Overview and Foundation have been released (albeit in draft form), before completion of some of the studies whose conclusions underlie the reports. In an election year, it is not unreasonable to wonder whether this might have a political motivation. At least one scientist involved in the report has stated that because of the election there was pressure to get the synthesis out before all the studies were completed (2). Others have questioned the fact that the report is more pessimistic about the magnitude of temperature increase in the U.S. than is the Intergovernmental Panel on Climate Change, an affiliate of the United Nations (3). Nevertheless, both of these critics agree that the report is the best current estimate of the seriousness of the problem. One of them said that, had it not been for the rush to produce the synthesis before the election, potential critics would have had nothing to say.

The process that produced this report is commendable. Involving everyone in evaluating scientific information and synthesizing it into a consensus report is likely to have a positive influence on public opinion and public policy. The report that resulted from this process (and about which public input continues to be solicited) is far more likely to move us to act rationally to try to solve the problems of global warming than would a scientific analysis that did not involve broad public input. It is unfortunate that there is still some question regarding political influence on the process, but the report is well worth your consideration--and that of your students. I strongly recommend that you read it, share it and discuss with students and colleagues, and draw your own conclusions regarding its correctness in assessing the problem.

Literature Cited

1. Climate Change Impacts on the United States: The Potential Consequences of Climate Variability and Change. Draft report of the National Assessment Synthesis Team, U.S. Global Change Research Program, Executive Office of the President, Office of Science and Technology Policy; http://www.gcrio.org/NationalAssessment/ (accessed Jun 2000).
2. Revkin, A. C. Report Forecasts Warming's Effects; The New York Times, June 12, 2000, p A1.
3. Easterbrooke, G. Warming Earth, Heated Rhetoric; The New York Times, June 14, 2000, p A31.