The Obama administration took a bold first step towards limiting the gases that cause global warming today after formally declaring that such emissions are a danger to public health.
The official finding by the Environmental Protection Agency that carbon dioxide and five other gases threaten public welfare sets the stage for regulation of emissions from coal-fired power plants, and for forcing US car manufacturers to make cleaner and more fuel efficient vehicles.
Environmentalists celebrated the ruling as the most definitive break to date with eight years of "climate denial" under George Bush.
The EPA said the science about the dangers posed by greenhouse gases was compelling and overwhelming, and that the increase of such gases was the unambiguous result of human emissions.
"This finding confirms that greenhouse gas pollution is a serious problem now and for future generations," the EPA administrator, Lisa Jackson, said in a statement.
The agency went further than some environmentalists had expected by making specific mention of auto emissions. The reference was seen as a signal that the EPA intended to allow California and more than a dozen other states to tighten restrictions on car exhaust.
The EPA's decision, known as an "endangerment finding", gives the agency the legal authority to demand cuts in emissions following a 60-day public review period.
That means the agency can begin regulating power plants and chemical and cement factories without waiting for Congress to undergo the laborious and uncertain process of turning a climate change bill that was unveiled last month into law.
The EPA did not suggest new regulations, and Obama has said repeatedly that he would prefer Congress to act on climate change through a comprehensive package of legislation. Jackson endorsed that position today.
Democratic leaders in Congress, while praising the EPA finding, also said the best way forward was to bring in new laws for a market-based cap-and-trade system.
But the EPA ruling – and the possibility of alternative action should Democrats fail to pass climate change legislation – raises the prospects that the Obama administration could put in place limits on greenhouse gases in advance of the Copenhagen climate change treaty.
"EPA, through its scientists, has given us a warning that global warming pollution is a clear, present and future danger to America's families," said Barbara Boxer, the chair of the Senate environment and public works committee. "If Congress does not act to pass legislation, then I will call on EPA to take all steps authorised by law to protect our families."
The supreme court directed the EPA two years ago to examine whether the gases should be monitored. But the Bush administration, opposed to regulation of CO2 emissions, stonewalled the move.
Environmentalists said the ruling now proved America would act on climate change. "There is no longer a question of if or even when the US will act on global warming. We are doing so now," said David Bookbinder, the chief adviser on climate change for the Sierra Club.
In a conference call earlier this week, he also said the EPA ruling would help negotiations for a climate change treaty at Copenhagen by showing the international community America was determined to act on global warming.
"The president will have done as much as possible in the 10 months between his inauguration and Copenhagen," Bookbinder said. "I think the rest of the world is smart enough to say, OK, he's off and running. He's heading in the right direction, and Congress is going in the right direction. We can do business with this guy."
Others were more guarded. Phyllis Cuttino, who directs the Pew Environment Group's US global warming campaign said, "The job isn't finished. The Obama administration can and must follow-up this decision and bring real leadership to Capitol Hill."
Industry groups, meanwhile, said the EPA finding would deepen the recession. The Competitive Enterprise Institute called the finding "an economic train wreck".
The EPA said its finding was based on a rigorous review of science on six greenhouse gases: carbon dioxide, methane, nitrous oxide, hydrofluorocarbons, perfluorocarbons and sulfur hexafluoride.
"In both magnitude and probability, climate change is an enormous problem," the agency said.
It said the consequences of increased concentrations of those gases in the atmosphere were drought, flooding, wildfires, heat waves, and rising sea levels that had especially adverse impacts on the poor.
Global warming also posed a national security threat, the EPA said.
Copyright Speakers Corner 2016