E.P.A. Rules Greenhouse Gases Dangerous, Sets Up Carbon Regulation

At a press event Monday afternoon in Washington, the Environmental Protection Agency announced that it has ruled greenhouse gases are a threat to public health, opening the door for the regulation of carbon emissions from automobiles, power plants, and other sources.

"These long-overdue findings cement 2009's place in history as the year when the United States government began addressing the challenge of greenhouse-gas pollution and seizing the opportunity of clean-energy reform," said EPA Administrator Lisa P. Jackson. "This continues our work towards clean energy reform that will cut GHGs and reduce the dependence on foreign oil that threatens our national security and our economy."

The agency has been studying the effects of greenhouse gas emissions and said its decision was made "after a thorough examination of the scientific evidence and careful consideration of public comments."

The announcement comes on the opening day of a high-profile world climate summit in Copenhagen, Denmark, which President Obama will attend later this week. Though the Senate has not passed legislation setting limits on carbon emissions, Obama could use the E.P.A.'s ruling as proof that the United States is taking serious steps toward implementing a stricter emissions policy. The House of Representatives passed a cap-and-trade-oriented bill earlier this year.