Political foes in agreement about global warming

On Tuesday, two other prominent politicians -- one a former presidential nominee, another toying with the idea of becoming one -- faced off before a packed house in an opulent Senate hearing room to discuss the same topic.

During their two-hour debate, Sen. John F. Kerry (D-Mass.) and former House Speaker Newt Gingrich (R-Ga.) agreed that climate change is a real concern that demands urgent action. Their disagreements came on the question of what to do next.

Gingrich called for tax breaks to promote greener technology and expressed faith that a free market could reduce greenhouse gases. "Rewarding entrepreneurship, investing in science and technology, reshaping the market with incentives are the fastest ways to get to change," he said.

But Kerry dismissed the notion that polluters would sufficiently reduce emissions on their own. Greater oversight is necessary, he said. "There is no single environmental crisis that has ever been met in the United States, or anywhere that I know of, voluntarily," he said. "The bottom line is that we've got to set a standard."

Backed by growing evidence of potentially dire consequences from a warmer planet, Democrats in Congress are attempting to refocus attention on the politically and economically contentious issue. Tuesday's debate was sponsored by the nonpartisan John Brademas Center for the Study of Congress at New York University.

Lionized by many conservatives for wresting congressional control from Democrats in 1994, Gingrich has been back in the spotlight in recent weeks, fueling speculation that he might jump into an already crowded race for the GOP presidential nod.

Kerry, who ran unsuccessfully against President Bush in 2004, is not seeking the 2008 nomination, a decision he announced after being criticized for saying -- in what he later described as a botched joke -- that if students didn't study hard, they would get "stuck in Iraq." Tuesday's event offered him a high-profile opportunity to flesh out his views on the environment -- the topic of "This Moment on Earth," a new book he wrote with his wife, Teresa Heinz Kerry.