Senators John McCain (R-AZ), Hillary Clinton (D-NY) and Barack Obama (D-IL) are among the speakers addressing global warming, taking up an open invitation from Sen. Barbara Boxer, who chairs the Senate Environment Committee.
Boxer said she wanted to hold the hearing so she could take the temperature of Congress before she launches into crafting climate legislation.
Sen. Joseph Lieberman and about two dozen other senators spoke on the issue. "I hope that when I'm done you'll put my temperature down as hot," Lieberman said. "Hot to get something done."
The presidential hopefuls McCain, Clinton and Obama had a similar message to Lieberman's, calling for action to fight climate change.
McCain, who co-sponsored a bill to cut emissions of the greenhouse gases with Lieberman and Obama, said that his trips to Greenland and the two poles had persuaded him of the urgency for action.
Boxer says she wants to hear the views of as many senators as she can, because she hopes to write climate-change legislation that can win the support of the vast majority of her colleagues.