President George W. Bush withdrew the United States from the international Kyoto treaty that seeks to reduce global warming emissions produced by mostly industrialized nations.

Bush said he feared the treaty's strict guidelines would harm the U.S. economy, and believed voluntary reduction emission programs would work better.

The European Union, which has adopted the Kyoto treaty, has strongly criticized the United States for not doing more to cut emissions. The United States is the world's biggest energy consumer and emissions producer.

U.S. carbon dioxide emissions totaled the equivalent of 1,540 million metric tons in 2001, down from 1,558 million metric tons the year before, according to preliminary estimates from the Energy Information Administration.

The 1.1 percent decline is the first drop since 1991, when emissions decreased by 1.2 percent.

"Because energy-related carbon dioxide emissions account for 81 percent of total U.S. greenhouse gas emissions, they are a good indicator of the level of, and rate of change in, total U.S. greenhouse gas emissions," EIA said.

U.S. energy-related carbon dioxide emissions have averaged a 1.2 percent annual growth since 1990, according to EIA, the Energy Department's statistical arm.

The reduction in U.S. manufacturing output in 2001 lowered industrial emissions, the agency said.

Ironically, warmer winter weather last year that many scientists blamed on global warming decreased the demand for heating fuels and electricity from coal-fired power plants, which reduced emissions growth from electricity generation.

While industrial emissions were down 9.1 percent from slower manufacturing activity, transportation sector carbon-dioxide emissions increased by 0.6 percent.