CHICAGO - PRESIDENT-elect Barack Obama on Monday named his energy and environmental chiefs and vowed a new dawn for US leadership to combat climate change after eight years of Republican foot-dragging.

Mr Obama nominated Nobel Prize-winning physicist Steven Chu as his energy secretary, placing the expert in renewable energy on the frontlines of climate change policy and ending the nation's 'addiction' to foreign oil.

'This will be a leading priority of my presidency and a defining test of our time. We can't afford complacency nor accept more broken promises,' the president-elect told a news conference.

'We won't create a new energy economy overnight. We won't protect our environment overnight. But we can begin that work right now if we think anew and if we act anew,' he said.

Joining Dr Chu will be Ms Lisa Jackson, chief of staff to the New Jersey governor, as head of the Environmental Protection Agency (EPA).

Mr Obama also appointed Ms Carol Browner, who served as EPA administrator under president Bill Clinton, to the new job of White House 'climate czar' overseeing the battle against global warming.

And Ms Nancy Sutley, a senior adviser to Mr Obama's transition team, was named chairwoman of the White House Council on Environmental Quality.

Despite an economic recession hitting the United States, Mr Obama is promising to unwind the environmental policies of President George W. Bush, whose refusal to ratify the Kyoto pact on climate change disgusted green campaigners.

Dr Chu, a scientist and Washington outsider, won his Nobel in 1997. Since 2004 he has been running the Lawrence Berkeley National Laboratory in California, which has a budget of US$645 million (S$951 million) and a staff of 4,000.

As energy secretary, Dr Chu will lead Mr Obama's ambitious agenda to generate 2.5 million new jobs through 'green' and new technologies aimed at making America more energy efficient and less reliant on foreign oil.

'We've seen Washington launch policy after policy, yet our dependence on foreign oil has only grown, even as the world's resources are disappearing,' Mr Obama said.

'This time must be different,' he said, promising to harness wind and solar power, new crops and new technologies, as part of an 'all-hands-on-deck effort' to remake the fossil fuels-based US economy.

Ms Jackson, who trained as a chemical engineer, vowed to restore teeth to the EPA, which during the Bush administration saw its funding slashed, scientific findings censored, and enforcement efforts downplayed.

In one notorious example, the EPA backed off a finding that said climate change was a risk to public welfare. The findings would have led to the nation's first mandatory global-warming regulations.

Despite the costs to industry as the US recession bites, Mr Obama has promised to set caps on domestic emissions of greenhouse gases and reposition the United States in the vanguard of international action.

'Some say we have to concentrate exclusively on re-establishing the health of the economy,' said Dr Chu, who if confirmed by the Senate will be only the second Chinese-American to serve in the US cabinet.

'I look forward to being part of the president-elect's team, which believes that we must repair the economy and put us on a path forward towards sustainable energy,' the acclaimed scientist said.

At UN climate talks in Poland last week, many delegates were delighted at the passing of the Bush administration as the international community attempts to craft a successor to the Kyoto pact.

But Mr Obama's room to manoeuvre may be curtailed by both the US recession and the limited time left before the deadline of December 2009 for completing a new UN climate treaty.

'Just as we work to reduce our own emissions, we must forge international solutions to ensure that every nation is doing its part,' Mr Obama said on Monday.

'As we do so, America will lead not just at the negotiating table. We will lead, as we always have, through innovation and discovery, through hard work and the pursuit of a common purpose.' -- AFP