In remarks to reporters, Obama made clear he would adopt an aggressive approach to global warming when he takes over the White House on January 20.

He and Vice President-elect Joe Biden met for nearly two hours with former Vice President Gore at Obama's presidential transition office in Chicago.

"All three of us are in agreement that the time for delay is over, the time for denial is over," Obama said.

Obama hopes addressing climate change can create the kind of jobs that will help pull the U.S. economy out of a deepening recession. He has begun to lay out plans for a massive recovery program to help stimulate the U.S. economy and create about 2.5 million jobs.

He said he would work with Democrats and Republicans, businesses, consumers and others with a stake in the issue to try to reach a consensus on a bold, aggressive approach to tackling the problem.

"This is a matter of urgency and of national security and it has to be dealt with in a serious way. That's what I intend my administration to do," Obama said.

Obama had a willing partner in Gore, who won a Nobel in 2007 for his years-long effort to educate people about the gradual warming of the planet and to argue against those scientists who believe a warming trend is a naturally occurring event.

There was no talk of offering Gore a job in the Obama administration. Gore has indicated he is not interested in a position of climate "czar" or any Cabinet post.

Just two days after Obama won the November 4 election, Gore's Alliance for Climate Protection rolled out a media campaign to push for immediate investments in energy efficiency, renewable power generation like wind and solar technology and the creation of a unified national power grid.

Gore and his group are in line with most U.S. environmental groups, which believe the Obama administration has a chance to stem global warming.

Critics have accused the outgoing Bush administration of stalling on the issue, but the White House insists it is taking steps aimed at addressing the problem without damaging the U.S. economy.

"We have the opportunity now to create jobs all across this country, in all 50 states, to re-power America, to redesign how we use energy, to think about how we are increasing efficiency, to make our economy stronger, make us more safe, reduce our dependence on foreign oil and make us competitive for decades to come, even as we're saving the planet," Obama said.