UPDATE 1-US Senate sets first global warming vote Thursday

(Debate begins, edits throughout)

By Chris Baltimore

WASHINGTON, Oct 29 (Reuters) - The Senate is expected on Thursday to cast its first-ever vote on whether to limit emissions of heat-trapping gases by power plants, factories and automobiles, a move the Bush administration opposes as too costly.

The bill -- which is likely to be rejected by the Senate -- would require reductions of so-called greenhouse gas emissions to 2000 levels by 2010.

Sens. John McCain, a Republican, and Joseph Lieberman, a Democrat, introduced legislation which would limit carbon dioxide emitted by coal-fired utilities, factories and vehicles. Many scientists say such gases prevent heat from escaping the earth's atmosphere and threaten to gradually submerge some island nations, disrupt crop-growing weather and change wildlife habitats.

Just getting the bill to the Senate floor was a victory of sorts for its sponsors, given strong Republican opposition.

McCain secured a promise from Senate leaders in July for six hours of debate on the issue in exchange for agreeing to support an energy bill proposal.

Lieberman, a Democratic presidential hopeful from Connecticut, said the Bush administration has failed to act.

"This president really is fiddling while the globe is warming and we'd better do something about it," Lieberman said during Senate debate that began on Wednesday evening.

"A healthy economy and a healthy environment are not mutually exclusive," Lieberman said. The United States, the biggest emitter of carbon dioxide in the world, has a "moral imperative" to begin limiting the gases, he added.

Kit Bond, a Missouri Republican, said there was no clear proof that human activities contribute to global warming.

Forcing industry to cap emissions will drive up the price of electricity, natural gas and gasoline, Bond said.

"Now is not the time to place more burdens on our families and communities," he said, adding that the bill would cost the U.S. economy billions of dollars and mean worker layoffs.

In an interview, McCain conceded the Senate would reject the climate plan, which is opposed by the Bush administration and industry who say it could harm a U.S. economic recovery.

"We're going to lose," McCain said. "But we want the debate to start and eventually we will win on this issue."

The vote scheduled for Thursday would be Congress' first poll on a measure to curb global warming.

President George W. Bush in 2001 withdrew the nation from participating in the global Kyoto treaty to cut carbon dioxide emissions to 5.2 percent below 1990 levels by 2008-12. More recently, the administration said it would not regulate carbon emissions from automobiles because it lacked congressional authority to do so.

Carbon dioxide caps face stiff opposition from industry-friendly Republicans. The National Association of Manufacturers said the bill would be "devastating" to economic growth and eliminate an estimated 600,000 jobs by 2012.

McCain and Lieberman said the bill's cap-and-trade mechanism for companies to buy and sell emissions credits is a market-oriented approach already used to reduce acid rain.

Environmental groups contend that global warming is a real and pressing crisis. To support their point, some point to a recent NASA study showing that the Arctic ice cap is melting at the rate of 10 percent per decade.

Passenger cars, pick-up trucks and sport utility vehicles account for about 20 percent of U.S. carbon dioxide emissions, while coal-fired power plants are responsible for 40 percent.