Democratic Senators, openly gleeful that years of fierce struggles against George W. Bush's Republican administration on the issue were drawing to a close, proclaimed the United States would undergo a "sea change" in environmental policy.

"The time to start is now," said Democratic Senator Barbara Boxer, vowing to step up to Obama's challenge to combat climate change and create millions of "green jobs" in the reeling US economy.

Her intervention came two days after Democrat Obama, in one of the few public policy pronouncements since his historic victory two weeks ago, told the world that "denial" would no longer be the US policy on climate change.

Boxer, chairwoman of the Senate Environment and Public Works committee, said one bill would combat harmful gas emissions by providing 15 billion dollars a year to spur clean energy innovation and the development of advanced biofuels.

The other piece of legislation will direct the US Environmental Protection Agency to set up a cap-and-trade system to stem greenhouse gas emissions.

"Instead of denial we will have resolve, instead of procrastination, we will have action. Instead of listening to the voice of the stagnant status quo, our committee hears the voice of our president-elect," Boxer said.

"We are facing a sea change," Boxer said, arguing that Obama's election and the big gains in congressional elections for Democrats would transform the attitude of the United States to global warming, the world's biggest polluter.

Independent Senator Bernie Sanders said Obama would transform US environmental policy.

"It's not only that you have a president who understands the severity of the problems, but he is willing to be aggressive in addressing it from a global warming perspective."

Boxer agreed. "We have a president now, President Bush, who simply felt the best action was voluntary, really no action, no action. And for all these years, we have wasted time."

It was not yet clear however if proponents of global warming legislation had the majorities in both chambers of Congress to push through action that some critics may see as damaging to the economy.

But in another encouraging sign for reformers, California congressman Henry Waxman, an advocate of global warming legislation, unseated Democrat John Dingell for the chairmanship of the House Energy and Commerce committee.

Dingell, 82, represents a district in auto-industry capital Michigan, and was seen as more hostile to attempts to cut greenhouse gas emissions.

On Tuesday, Obama told a California-based meeting of US governors and global warming experts in a video-taped message that he would "engage vigorously" in global climate change talks.

The president-elect also addressed his message directly to delegates at United Nations climate change talks in Poland next month.

"Once I take office, you can be sure that the United States will once again engage vigorously in these negotiations, and help lead the world toward a new era of global cooperation on climate change.

"Now is the time to confront this challenge once and for all. Delay is no longer an option. Denial is no longer an acceptable response. The stakes are too high. The consequences, too serious."

Obama has called for annual targets that would aim to reduce emission levels to 1990 levels by 2020 and then by an addition 80 percent by 2050.

Boxer said she was not yet ready to reveal details of the legislation but said it would be consistent with Obama's policy goals.

Democratic Senator Amy Klobuchar meanwhile said she would be the committee's representative at the Poland talks.

She said she would tell other world leaders at the conference, which Obama will not attend, "that there is a new cop in town."

"We are moving forward on climate change, and there is going to be a difference with these past eight years of inaction with this administration."

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