* Senator Boxer hails "great signal" to Copenhagen
* Republicans boycott committee vote
* Senator Baucus says opposes 20 pct carbon cut target (Adds reaction in paragraphs 6-9)
By Richard Cowan
WASHINGTON, Nov 5 A controversial climate change bill cleared its first hurdle in the U.S. Senate on Thursday, allowing President Barack Obama to tout progress in the run-up to next month's global warming talks in Copenhagen.
Democrats on the Senate Environment and Public Works Committee ignored a Republican boycott and used their majority to approve the legislation that would require U.S. industry to reduce emissions of carbon dioxide and other greenhouse gases 20 percent by 2020, from 2005 levels.
"I think this is a great signal for Copenhagen that there's a will to do what it takes to advance this issue," committee Chairman Barbara Boxer told reporters after her panel voted.
The committee vote also came as international negotiators held a contentious climate change meeting in Barcelona, their final session before the Copenhagen summit starts Dec. 7.
But Democrats are likely to fall far short of their goal of passing legislation in the full Senate before Copenhagen as Boxer's bill lacks enough support for full approval.
Senate Majority Leader Harry Reid indicated as much. While he applauded the environment panel's vote, he said, "There is much more work yet to do to obtain broad support" for a bill.
Tuesday's election, which saw conservative Republicans capture governors' seats in New Jersey and Virginia, could embolden some Republicans to ramp up opposition to climate change legislation.
"This bill will send energy costs racing upward and put the brakes on any hope of economic recovery," said Representative Jim Sensenbrenner, a Republican. "Once the American public starts paying for these special interests, Democrats may not have much to hope for in future elections either."
Some environmental groups praised the Senate panel's action on the bill. Eric Haxthausen, director of climate policy for The Nature Conservancy, said it "helps clear a path forward on climate and energy legislation."
The Union of Concerned Scientists urged that the 20-percent carbon reduction goal not be weakened.
Senator John Kerry, who co-authored the committee-approved bill with fellow Democrat Boxer, is leading an effort with some Republicans and the White House to draft a compromise.
With all seven Republicans chairs empty in the Senate environment panel's hearing room, 11 Democrats voted to approve the bill. Only one Democrat, Senator Max Baucus, who chairs the powerful Senate Finance Committee that also will review climate legislation, voted no.
AREAS OF COMPROMISE
Before casting his vote, Baucus said he was committed to passing a bill to tackle global warming. But he said the goal of cutting carbon emissions from utilities, factories and oil refineries by 20 percent by 2020 was too high.
Baucus said he would seek a 17 percent goal, with a "trigger" to hike it up to 20 percent if other countries "play by the same rules" in cutting their carbon emissions.
A climate bill that narrowly passed the U.S. House of Representatives in June sets a 17-percent target for 2020.
Baucus' vote against the bill reflects the difficulties ahead in crafting a measure that would have to attract the 60 votes needed for passage by the Senate.
Other senators from Midwestern and Southern states heavily reliant on coal will seek their own changes, which could upset liberals now supporting the bill.
There is widespread expectation in the Senate that for any climate control bill to pass, it will have to contain new government incentives for expanding U.S. nuclear power-generating capacity and offshore oil drilling, along with money to help develop clean ways to burn coal, which is abundant in the United States.
There were scores of amendments to Boxer's bill that environment committee members wanted to debate and vote on before approving it, but they were unable to because of the Republican boycott.
Under committee rules, at least two Republicans had to be present to debate and vote on changing the bill.
Boxer delayed work on the legislation for two days, saying she was giving Republicans the opportunity to collect more information from the U.S. Environmental Protection Agency and to offer their own amendments.
But Republicans did not take her up on the offer and by Thursday, Boxer had lost patience with the delay. (Editing by Xavier Briand)