Last month, the climate bill came out of the House of Representatives as a bloated 1,400-page document that experts say has little chance of slowing global warming.

Can the Senate do any better? That’s one of the questions Sen. Barbara Boxer, a California Democrat, faced as the pending legislation arrived on her turf at the Environment & Public Works committee hearings this morning.

The proposed Senate bill holds the potential to put a cap on climate-warming gases, spark innovation in the renewable energy sector, and boost green jobs around the country, but it also has to wend its way through five additional Senate committees before it goes to vote in September.

“Today, I expect you will hear fierce words of doubt and fear and worse from the other side of the aisle regarding our legislative efforts to move forward with clean energy jobs legislation,” Boxer said. “This is consistent with a pattern of ‘No, we can’t.’”

Indeed, after four top Obama administration officials testified before the committee, emphasizing the well-known threats of climate change, Republican Sen. John Barrasso of Wyoming mounted a cynical offensive on the head of the U.S. Environmental Protection Agency, Lisa Jackson.

Barrasso brought up a recent Washington Post article deconstructing the flaws in the House climate bill, and he asked Jackson whether the bill would have an impact on climate change. Jackson agreed that the legislation had shortcomings but said that it still “sends a strong signal, and you all in the Senate have work to do.”

Barrasso also repeated claims by the Competitive Enterprise Institute that the Obama administration gagged two climate change dissenters in the EPA and later “smeared” the name of an attorney who opposed using the Clean Air Act to regulate climate change by calling him a “Bush appointee.” Jackson provided a point-by-point rebuttal to the gag claim and smirked as she promised to “check on” the latter accusation.

Another Republican senator, James Inhofe of Oklahoma, turned out to have more substantial critiques to voice during the hearings. He pointed out that the U.S. could not slow down global warming without getting China, India and other developing nations on board to cut emissions. China had recently surpassed the U.S. as the world’s number one emitter of greenhouse gases, and Inhofe noted that five signatories of the Kyoto protocol were backing out.

Neither Jackson nor other administration officials were able to give a convincing rebuttal to the challenge except to say that the U.S. has an obligation to be a leader. Indeed, President Obama currently has international climate policy on his plate this week at the annual summit of the Group of Eight (G8) leading industrialized nations in L’Aquila, Italy.

Environmental organizations have been hoping that the Senate will be able to beef up the climate bill before President Obama signs it into law as he has vowed to do. But Nate Silver, the analyst who runs the blog FiveThirtyEight, was skeptical that the Senate can get 60 votes to pass it without making some serious compromises. “The question is how many ornaments the Democrats could place on the Christmas tree before it starts to collapse under its own weight,” he wrote.

Image of Barbara Boxer courtesy Korean Resource Center via Flickr