WASHINGTON » It’s a lot of hot air about a lot of hot air.

Democrats took to the Senate floor Monday night to talk about global warming and planned not to let up until morning. By midnight, lawmakers had been talking for nearly six hours.

Leading off the dusk-to-dawn talkathon, Senate Majority Leader Harry Reid, D-Nev., called climate change "a question of our own survival" and said the United States and other countries have a responsibility to act "before it is too late."

At least 28 senators were expected to participate. But several Democrats who face tough re-election fights in the fall opted to skip the session. Sens. Mary Landrieu of Louisiana, Kay Hagan of North Carolina, Mark Pryor of Arkansas and Mark Begich of Alaska were among them.

Democratic leaders have no plans to bring a climate bill to the Senate floor this year, so the speeches were little more than theatrics. House Democrats pushed through a bill to limit greenhouse gas emissions blamed for global warming in 2009, then lost their majority the following election.

A climate bill led by then-Massachusetts Sen. John Kerry collapsed in 2010 without a vote in the Democratic-controlled Senate.

Sen. Brian Schatz, D-Hawaii, one of the organizers, said the all-night session showed that a growing number of senators are committed to working together to confront climate change.

"Climate change is real, it is caused by humans, and it is solvable," Schatz said.

But Sen. James Inhofe, an Oklahoma Republican who has written a book denouncing global warming as "the greatest hoax," said Democrats would not convince anyone with their stunt.

"They’ll have an audience of themselves, so I hope they enjoy it," Inhofe said. Indeed, he was one of only a few Republicans who engaged in the debate. None sided with Democrats.

Sen. Barbara Boxer, D-Calif., retorted that Democrats had received two separate petitions urging them to act, with a total of about 100,000 signatures.

"The American people are listening," Boxer said. "They care." 

She added that the event should "wake up Congress to the dangers of climate change."

Boxer and Sen. Sheldon Whitehouse, D-R.I., lead the recently launched Senate Climate Action Task Force, which organized the session.

Whitehouse said the session was needed to highlight obstacles to climate legislation, including ads financed by Charles and David Koch, conservative activists who have spent $15 million on Senate races, mostly criticizing Democrats over Obamacare. The Koch brothers, whose interests include oil, chemicals, textiles and paper, have also spent millions on ads critical of action against climate change.

Whitehouse conceded that lawmakers do not have the 60 votes needed to act on the matter, even in the Democratic-controlled Senate, but said the speeches could help change the dynamic.

"Tonight is not about a specific legislative proposal," he said. "It’s about showing the environmental community, young people and anyone paying attention to climate change that the Senate is starting to stir and we want to get some actions going."

The episode followed overnight speeches last year by Republicans Sens. Rand Paul of Kentucky and Ted Cruz of Texas. Paul criticized U.S. drone policy, while Cruz pushed to take money away from the new health care law.

While some Democratic senators weren’t on board, Whitehouse said the major differences in the debate are between the two parties.

"There are no climate (change) deniers in the Senate Democratic caucus," he said. "There may be a divergence of views on what the appropriate solution is, but nobody is out there pretending this isn’t real (or) that this is a hoax."

White House spokesman Jay Carney praised the participants for bringing attention to "a very important subject that the president is concerned about." He cited a climate action plan announced by Obama last year. 

The plan would impose the first-ever limits on carbon pollution from new and existing power plants, as well as boost renewable energy production on federal lands and increase energy efficiency standards.

Senate Minority Leader Mitch McConnell, R-Ky., said the talkathon amounted to "30 hours of excuses" from senators who think it’s OK that "families are losing work because of government attacks on the coal industry."

"Well it’s not OK, it’s cruel," McConnell said, speaking on the Senate floor before the talkathon began. "It’s cruel to tell struggling coal families that they can’t have a job because some billionaire from San Francisco disagrees with their line of work."

McConnell was referring to Tom Steyer, a former hedge-fund manager and environmentalist who says he will spend $100 million — $50 million of his own money and $50 million from other donors — to make climate change a top-tier issue in the 2014 elections. Steyer spent millions to help pass a California ballot measure to boost spending on energy efficiency programs and help elect Democrats Terry McAuliffe as Virginia governor and Edward Markey as U.S. senator from Massachusetts.

"We hope that by standing up all night to talk about climate, that tomorrow will signal a new dawn," Markey said.