Environmentalists in the United States say they hope the removal of global-warming sceptics from powerful positions on Capitol Hill will present a new opportunity to force the Bush administration to tackle climate change.
This week's seizure of both houses of Congress by the Democrats means that two key Republican opponents of action to confront climate change - Senator James Inhofe of Oklahoma and Richard Pombo of California - will lose their positions as the chairmen of Congress's two environmental committees.
Mr Pombo, who lost his bid for re-election, will leave the House altogether. Mr Inhofe, who once said the threat of global warming was, "the greatest hoax ever perpetrated on the American people", will probably be replaced by the California Democrat Barbara Boxer. She has promised to curb carbon emissions and strengthen environmental protection legislation.
"I think this represents a huge shift in the political dynamic of environmental politics," said Karen Wayland, legislative director of the National Resources Defence Council, a environmental group in Washington.
"I think that Mrs Boxer knows that she has been an environmental champion ... but that she will have to do more to build consensus. I think she will be very aggressive on global warming.
"When Mr Inhofe held hearings he called the science fiction writer Michael Crichton [a global warming sceptic] as his main witness."
In a statement, Friends of the Earth International, said: "Tuesday's midterm elections offered a stunning rebuke to the Bush administration's pro-oil, anti- environment agenda.
"The change in leadership and the defeat of some of Congress's most anti-environmental members offers hope for the millions of Americans who support stronger environmental protections and are eager for a clean energy future."
On Thursday, Mrs Boxer, the ranking Democrat on the Senate Environment and Public Works Committee, told reporters that in addition to pursuing a policy shift in regard to climate change and environmental protection, she would also seek to do more on cleaning up toxic waste.
"Time is running out, and we need to move forward on this," she said. "The states are beginning to take steps, and we need to take steps as well."
She said she would seek to pass legislation based a California state law signed this summer by Governor Arnold Schwarzenegger which imposes a cap on greenhouse gases and seeks to cut emissions by 25 per cent, dropping them to 1990 levels by 2020.
Under President George Bush the US government has been strident in resisting international and domestic calls to act on climate change. One of the first things Mr Bush did on coming to office was to withdraw support for the Kyoto treaty, which called for 35 industrialised nations to cut emissions by 5 per cent below their 1990 levels by 2012. Mr Bush said it would be too damaging to the country's economy and would cost five million jobs.
At a UN climate summit last year in Montreal, the US resisted calls to even talk about establishing fixed limits, saying it believed that reductions could be made voluntarily and by use of improved technology.
The US is responsible for 25 per cent of the world's CO2 emissions.Reuse content