In crafting the U.S. response to global climate change, the president said congressional lawmakers must take into account the real price of America's heavy reliance on petroleum-based energy.

"If we refuse to take into account the full costs of our fossil fuel addiction - if we don't factor in the environmental costs and the national security costs and the true economic costs - we will have missed our best chance to seize a clean energy future."

High costs

A new report by the PEW Center on Global Climate Change, an independent policy research group, echoes the president's view. But it adds that, even if aggressive policies are put in place to reduce future carbon emissions, steps must be taken now to adapt to greenhouse gases already in the atmosphere; emissions that will continue to pollute the air and affect the earth's climate.

And who should lead that effort?

PEW Vice President for Policy Analysis and the report's co-author, Stephen Seidel, says the federal government should lead, as the nation's largest landowner and the guardian of its natural resources, national parks and highways, bridges and dams.

"What the federal government does, has a huge impact on where we build in coastal zones, how we farm, what our infrastructure looks like," says Seidel. "And so decisions that federal agencies are making will have an enormous impact in our ability to wisely adapt to climate change."