WASHINGTON -- An expert panel of the National Academy of Sciences urged the Bush administration yesterday to undertake "promptly" a set of anti-pollution and energy efficiency measures that it said would slow global warming without putting strain on the economy.
The report by more than 50 scientists, economists and public policy experts could have significant influence on national energy policy and environmental legislation now under consideration by Congress, environmental groups predicted.
They said it would also undercut the position of some White House and administration officials who have resisted energy conservation initiatives on the grounds that there is not enough scientific evidence about global warming to justify what they regard as unduly expensive countermeasures.
The panel addressed the issue head-on, saying in its report that "despite the great uncertainties, greenhouse warming is a potential threat sufficient to justify action now."
The report's recommendations amounted to "a planetary insurance policy," former Sen. Daniel J. Evans, R-Wash., chairman of the leading panel of the inquiry, said yesterday.
While there is still inadequate scientific knowledge about global warming, he said, the researchers believed it would be prudent to take measures now to avoid having to embark on expensive remedies later.
"Proposals we have made are low-cost and in some cases can be acquired at a net savings," he said.
The study was initiated in the sweltering summer of 1988, when Congress asked the Environmental Protection Agency to commission the academy to study global warming and recommend actions to mitigate its causes and effects.
The result is seen as something of a policy turnaround by the influential, scientifically conservative academy. In a similar study reported in 1983, the academy concluded that there was no need to change existing patterns of dependence on fossil fuels.
"I think this is one of the most important things we've done in recent years," said Frank Press, president of the academy. "I expect this report will play an important role as this country develops its environmental and energy policies."
EPA Administrator William K. Reilly said the report "advances our understanding of one of the biggest environmental issues we confront."
The Bush administration, he said, would "seriously review and consider" the panel's recommendations.
"The academy report demolishes any remaining defense that the administration has for its inaction," said Michael Oppenheimer, chairman of the Environmental Defense Fund's global atmosphere program.
Sen. Al Gore, D-Tenn., a leading environmental legislator, praised the report's recommendations for phasing out greenhouse gases, saying they showed clearly "the seriousness the global warming threat." But the recommendations in general, he said, "fall far short of what's needed."
The academy's panel accepted earlier scientific models that predict that the atmospheric levels of carbon dioxide and other gases believed to cause global warming are rising so fast that the Earth's average temperature could increase by an unprecedented 2 degrees to 9 degrees in the next 50 to 60 years.
The results could not be accurately predicted, the panel said, but they could include tidal floods, the swamping of coastal communities and the desertification of fertile regions, with the consequent economic collapse of some agriculturally dependent nations and the extinction of climate-sensitive species.
Many scientists believe that rising levels of industrial emissions, automobile exhaust gases and other pollutants such as chlorofluorocarbons -- a family of compounds that includes refrigerant gases and most aerosol propellants -- have upset the Earth's ecological balance, causing global temperatures to begin rising gradually, with potentially climate-changing effects.
The panel's central concern was to reduce greenhouse gas emissions. The most important reduction, it said, would be the "aggressive phaseout" of CFCs in accordance with, and ideally ahead of, the timetable in the 1990 London Protocol.
It also recommended energy conservation and efficiency measures, increased research into alternative energy supplies and research into new-generation nuclear reactors.