With climate change legislation heating up, liberal advocates are taking aim at the U.S. Chamber of Commerce, which has been skeptical of recent legislative moves to deal with global warming.

A petition organized by MoveOn.org that asks the chamber to stop lobbying against President Barack Obama’s clean-energy bill has already garnered the names of more than 10,000 small-business men and women, 650 of whom are also chamber members.

The signatories are self-identifying Chamber of Commerce members, according to the group’s project manager, Noah T. Winer.

“Here are small businesses joining this fight and saying this doesn’t represent our business interests, much less our political ones,— Winer said.

Five people, including a small-business owner from Maryland, delivered the petitions Tuesday to Karen Harbert, the president of the U.S. Chamber of Commerce Institute for 21st Century Energy, according to Winer.

Tom Benson, owner of the World’s Largest Laundromat in Berwyn, Ill., signed the petition. He uses solar panels on the roof of his laundromat to help defer energy costs.

“I don’t think the business community ought to do knee-jerk reactions to something just because there’s a change in the ballgame,— Benson said. “That’s reality and you have to deal with it.—

Lately, a growing segment of the business community is making positive gestures about a climate change bill sponsored by the House Energy and Commerce Chairman Henry Waxman (D-Calif.) and Subcommittee on Energy and Environment Chairman Ed Markey (D-Mass.).

The chamber’s Bruce Josten, however, was skeptical of the 650 “chamber— signatures, saying that many local and state chambers are not necessarily members of the national business group.

“I’m happy to hear they all think they are our members,— Josten said, noting that the chamber represents 3 million businesses.

And Josten stressed that so far, at least, the chamber hasn’t worked up a formal position on the climate change bill. “We have never stated firm opposition to any federal regulation that requires reduction in greenhouse gas emissions,— Josten said.

The group has raised several problems with the bill, questioning the inclusion of citizen lawsuits, among others.

MoveOn.org’s push comes days after Nike and Johnson & Johnson wrote to the chamber, asking it to stand down on climate change.

“Members are starting to get fed up that they are not a positive advocacy tool anymore,— said one lobbyist familiar with the chamber’s membership.