Democratic leaders in the House and the Senate, and both presidential candidates, continue to rank tackling global warming as a chief goal next year. But the focus on stabilizing the economy probably will make it more difficult to pass a law to reduce carbon dioxide and other greenhouse gases. At the very least, it will push back when the reductions would have to start.

"Clearly it is somewhere down the totem pole given the economic realities we are facing," said Tom Williams, a spokesman for Duke Energy Corp., an electricity producer that has supported federal mandates on greenhouse gases. Duke is a member of the US Climate Action Partnership, an association of businesses and nonprofit groups that has lobbied Congress to act.

Just months ago, chances for legislation passing in the next Congress and becoming law looked promising. The presidential candidates support mandatory cuts and a Democratic majority is ready to act on the problem after years of the Bush administration resisting federal controls.

But the most popular remedy for slowing global warming, a mechanism know as cap-and-trade, could put further stress on a teetering economy.

Under such a system, the government would establish a market for carbon dioxide by giving or selling credits to companies with operations that emit greenhouse gases. The companies can then choose whether to invest in technologies to reduce emissions to meet targets or instead buy credits from other companies who have already met them.

In an interview with The Associated Press, Rep. Rick Boucher, a Virginia Democrat, said that in light of the economic downturn, a bill that would give polluters permits free of charge would be preferable.

"The first way we can control program costs is by not charging industrial emitters," said Boucher, who released a first draft of a bill this past week with the chairman of the House Energy and Commerce Committee, Rep. John Dingell, a Michigan Democrat. Giving away right-to-pollute permits was one of the options.

Other Democrats, however, see a cap-and-trade bill, and the government revenues it would generate from selling permits, as an engine for economic growth. Democratic presidential nominee Barack Obama supports auctioning off all permits, using the money to help fund alternative energy.

"If you see this as a job creation opportunity for the US to develop the products that are then sold around the world, then you should be optimistic about what the impact of passage would mean for the American economy,'' said Rep. Edward Markey, a Massachusetts Democrat.

Conservative Republicans who were never fans of a law to curb greenhouse gases have used the economic downturn as a rallying cry.

Oklahoma Sen. James Inhofe, the senior Republican on the Senate Environment and Public Works Committee, in a blog entry this month criticized 152 House members for releasing a set of principles to tackle global warming in the midst of the economic turmoil.

"The current economic crisis only reinforces the public's wariness about any climate bill that attempts to increase the costs of energy and jeopardizes jobs," Inhofe said.

Rep. Joe Barton, a Texas Republican, took the argument a step further when he said the Boucher-Dingell bill could lead the country ``off the economic cliff.''

But even supporters of federal regulation of greenhouse gases acknowledge that something has to give given the state of the economy.

Republican Sen. John Warner of Virginia, a lead sponsor of a Senate bill to curb greenhouse gases that failed this year, acknowledged that the economy could delay when reductions in carbon dioxide would start.

Warner said that any bill should allow the president to decide.

"We must continue to think and devise a piece of legislation that will enable the president of the United States to control timing ... dependent on the president's analysis for the ability of the economy to assume the financial burdens," said Warner, who is retiring from the Senate and not seeking re-election this year.

The US is not alone. As the economic crisis has spread to markets across the globe, work to curb greenhouse gases elsewhere has stalled.

Earlier this past week, Rajendra Pachauri, head of the U.N. climate panel, said discussions about global warming solutions were ``on the back burner.'' Pachauri shared the 2007 Nobel Peace Prize with former U.S. Vice President Al Gore for their work on climate change.

``I'm absolutely sure that climate change will be the last thing people will think about at this point in time,'' he said. ``Sooner or later, they will come back to it.''

The upside is that in hard economic times, and with high energy prices, the amount of pollution in the air tends to decline.

That will slow global warming somewhat, but there are already enough heat-trapping gases in the atmosphere to cause the temperature to rise.

``I really wish that the science of global warming would look at the newspaper, and say we have an economic crisis so the Earth will stop warming,'' said Dave Hamilton, director of the Sierra Club's global warming and energy program. ``But that is not going to happen.''