WASHINGTON - President Clinton called yesterday for new federal regulations limiting power plants' emissions of carbon dioxide, a gas thought to cause global climatic change, through a system similar to the rules in place for pollutants that cause smog and acid rain.
It would be the first time federal regulations would specifically control emissions of carbon dioxide, the main so-called greenhouse gas. Clinton called for similar controls on emissions of mercury, another pollutant that is given off by some power plants but is not regulated under air pollution laws.
Such an expansion of pollution rules would likely require action by Congress, where there is significant opposition. But the administration argued that without this step, an international treaty to reduce the risk of global warming would probably fail.
Clinton proposed a "cap and trade" system, under which the government would set a national limit on emissions and divide pollution allowances among power plants. Companies could cut their emissions enough to stay within their allowances. Or they could cut more of their emissions and sell the leftover allowances to companies that might cut their emissions less extensively and therefore need more allowances.
The idea, a market-based approach applied to other forms of air pollution since the early 1990s, is meant to get the desired reductions at the least cost.
But many in Congress oppose unilateral steps by the United States to regulate greenhouse gases, and many oppose the Kyoto Protocol, a climate-change treaty negotiated in 1997 in Kyoto, Japan, that the United States has signed but not submitted to the Senate for ratification. The United States is by far the world's biggest emitter of carbon dioxide.
Clinton's proposal comes as United Nations members are gathering in The Hague, Netherlands, to discuss ways to implement the Kyoto Protocol.
"The scientific consensus is clear: The earth is warming, and there is strong evidence that human activity is part of the reason why," the president said in an address broadcast yesterday over the Internet so international delegates could have access to it. The speech is posted at the White House Web site, www.whitehouse.gov.
Clinton did not provide numbers for how extensively emissions should be cut.
He also did not specify how companies could generate allowances for sale. However, technicians say they could burn fuel more efficiently or switch from coal to natural gas, which produces less carbon dioxide. That would also reduce emissions of mercury and other pollutants. Power companies could also plant trees or pay to prevent tree cutting. Trees take carbon dioxide out of the air and store it in growing wood.
