Senate Finance Chairman Max Baucus said today that he has "serious reservations" about a major global warming bill and warned fellow Democrats to water down the measure in hopes of getting it through the Senate.

Speaking at the start of an Environment and Public Works Committee hearing where he is the second highest-ranking member, the Montana Democrat said he wanted to weaken the bill's 2020 target for greenhouse gas emissions -- now 20 percent below 2005 levels. He did not name a specific midterm target for the heat-trapping gases, instead telling reporters he hoped for "some modification."

The six-term senator also said he hoped to attach pre-emption language to the Senate climate bill, S. 1733, that stops U.S. EPA from implementing a 2007 Supreme Court opinion that opens the door to new greenhouse gas emission standards on industry.

"We cannot avoid a first step that takes us further away from an achievable consensus from common-sense climate change legislation," Baucus said. "We could build that consensus here in this committee. If we don't, we risk wasting another month, another year, another Congress, without taking a step forward to our future."

Baucus chaired the environment committee from 1993 until 1995, and his centrist voice carries tremendous weight in the party's leadership ranks. But Democrats also have a 12-7 majority on the EPW Committee, and his vote likely won't be necessary as Chairwoman Barbara Boxer (D-Calif.) looks to move the bill in the coming weeks.

Instead, Boxer and Democrats face the critical question of whether they should wait to deal with Baucus later in the negotiations, as his concerns foreshadow a tough fight to win the 60 votes needed to pass a comprehensive bill.

"Certainly, his views are going to be heard, and his views are going to be taken into account mostly because he is similar to many other fence-sitters that are key to this," said Frank Maisano, an industry lobbyist for Bracewell & Giuliani, citing other senators from coal-producing and rural states, like Democrats Byron Dorgan and Kent Conrad of North Dakota and Blanche Lincoln of Arkansas.

Baucus, who plans Finance Committee hearings next month on several issues central to the legislation, opened today's session saying he is willing to support a climate bill, albeit with caveats.

"The legislation before us is about our economy," Baucus said. "Montana, with our resource-based agriculture and tourism economies, cannot afford the unmitigated impacts of climate change. But we also cannot afford the unmitigated affects of climate change legislation. That's why I support passing common-sense legislation that reduces greenhouse gas emissions while protecting our economy. The key word in that sentence is 'passing.'"

Sen. Arlen Specter (D-Pa.), another critical moderate vote on the environment panel, warned senators on both sides of the aisle about the "very heavy political overtone at the start of these hearings."

Specter, who faces a tough Democratic primary race next year, pushed back against committee Republicans who warned about the dire economic consequences that would come from passing the Senate climate bill.

"We're all concerned about job loss," Specter said, adding that he hopes to work on legislation that can win the backing of industry, environmentalists and labor groups like the United Mine Workers of America.

Like Baucus, Specter said he is looking to change the Senate bill's 2020 emission targets, but he refused to go far in sizing up what is needed to win his vote.

"Every part of the bill is now under analysis," Specter said. "We're wading through a very complex piece of legislation. And there are going to be a lot of factors to consider, and I'm not prepared to make a judgment before the opening statements are made."

House Democratic leaders had originally sought a 20 percent emissions limit for 2020 but backed down to 17 percent after negotiations with lawmakers who represent districts with heavy industry influence. The House passed its bill, H.R. 2454, in June.

EPW Committee provides 'the foundation' -- Kerry

In all, six Senate committees and Majority Leader Harry Reid (D-Nev.) will have a say in what goes into the final climate bill that comes up on the floor for a vote, likely early next year. But the Democrats' point person on the climate legislation, Sen. John Kerry (D-Mass.) said the EPW panel remains critical to that effort.

"The foundation of all that has to come through this committee," Kerry said at the end of a 25-minute opening statement that launches three days of EPW Committee hearings. Several top Obama administration officials also testified today, including U.S. EPA Administrator Lisa Jackson, Energy Secretary Steven Chu, Interior Secretary Ken Salazar, Transportation Secretary Ray LaHood and Federal Energy Regulatory Commission Chairman Jon Wellinghoff.

Kerry, the chairman of the Foreign Relations Committee, listed reasons for moving the climate bill -- from threats to U.S. national security to the potential for economic growth. He also highlighted the international significance that comes with progress in the Senate.

"America's leadership is certainly on the line here," Kerry said.

Senate Republicans pushed back against the Democrats' plans to move the bill as early as next week.

Ohio's George Voinovich questioned whether senators have a firm grip on the implications of the legislation, as well as the quality of a U.S. EPA analysis released late Friday that did not actually include any new modeling runs on the at-issue bill.

"Why are we trying to jam down this legislation now?" Voinovich asked. "Wouldn't it be smarter to take our time and do it right like we didn't do it the last time around when we had this legislation in the works?"

Boxer touted EPA findings that say the legislation she co-authored with Kerry would cost the average American household between 22 cents and 30 cents a day.

"No climate bill has ever had this level of review, and the Obama administration stands behind this analysis," Boxer said, explaining that EPA spent five weeks studying the House-passed bill and then worked for another two weeks on the Kerry-Boxer approach.

The Kerry-Boxer bill, she added, "is the best insurance against a dangerous future. It is a responsible approach that sets attainable goals for gradual reductions in carbon emissions and it protects consumers, businesses and workers as we move toward clean energy."

Boxer also replied to Republicans' complaints that they have not had enough time to review the bill, saying she is well within the committee rules by circulating the chairman's mark 10 days before a potential markup.

The California Democrat added that she wants to add GOP supporters but would not wait for that to happen.

"This need for bipartisanship, believe me, I'd give anything if had a John Warner still sitting here," she said, referring to the retired Virginia Republican senator who led last year's Senate debate.

"We don't have it. Climate change, global warming isn't waiting for who's a Democrat or who's a Republican," Boxer said. "Either we're going to deal with this problem, or we're not."

Reprinted from Greenwire with permission from Environment & Energy Publishing, LLC., 202-628-6500