WASHINGTON -– Senators planning to stay up all night Monday talking about climate change say the marathon session is the "opening salvo" in a renewed effort to pass legislation curbing greenhouse gas emissions.

"We have a simple message for all Americans: We're not going to rest until Congress acts on the most pressing issue of our time," said Sen. Brian Schatz, a freshman Democrat from Hawaii, who organized the all-nighter on the Senate floor.

The overnight session is meant to "make sure everybody across the nation knows we're taking this seriously, and that there is a stirring in the Senate on this issue," said Schatz. Participants said they will make the point that climate change is "real, caused by humans, happening now, and it is solvable," he said. "We are the cause, but we are also the solution."

Thirty senators have signed up to participate in the event, including Sens. Jack Reed (D-R.I.) and Chris Coons (D-Del.), who joined the lineup since it was announced on Friday.

Sen. Sheldon Whitehouse (D-R.I.) said that while the senators don't plan to introduce legislation during the session, they hope the event will show strong support for action among Senate Democrats. "Tonight's event is a signal of a much larger confidence we have about our ability to get a significant climate bill passed in Congress," said Whitehouse. "We have a very strong chance to win, but we have to fight."

The push is notable. It was the Democratic-led Senate that killed climate legislation in 2010, after the House had passed a major cap-and-trade bill the previous year. Senate Majority Leader Harry Reid (D-Nev.) said at the time that the measure didn't have enough votes to move forward. Reid has been taking a more aggressive stance on climate recently, telling reporters last week that climate change "is the worst problem facing the world today."

More than half of the Senate Democratic caucus is participating in the overnight session. On a call with reporters Monday afternoon, Whitehouse was asked about the 25 Democrats who aren't -- including a number of from fossil-fuel producing states and those facing tough reelection bids in 2014. "There are no climate deniers in the Senate Democratic caucus. There may be a divergence of views on what the appropriate solutions are, but no one is out there pretending this isn't real or it's a hoax," said Whitehouse. "This is just an opening salvo, and as we bring more and more voices into this, we'll be in a better position to not only have a unanimous caucus on this problem, but have a unanimous caucus on the solution."

"Actually, there's a pretty good group to work with," said Whitehouse. He said an influx of corporate money into electoral campaigns following the Supreme Court's 2010 Citizens United decision has driven Republicans "back to their holes" on climate change. He said he hopes the all-night session will help "spotlight" the issue "so they're obliged to work with us."

"We hope by staying up all night to discuss climate change, tomorrow will signal a new dawn for climate action in Congress," said Sen. Ed Markey (D-Mass.).