WASHINGTON, Dec 16 (Reuters) - Here's what leading U.S. presidential candidates have said about climate change, and what they want to do about it.

DEMOCRATIC NEW YORK SEN. HILLARY CLINTON: "We need to start on a path to slow, stop and reverse the growth of greenhouse gas emissions." Supports an 80 percent reduction in carbon emissions by 2050, 40 mile-per-gallon fuel efficiency standard by 2017 and 10 percent cut in energy consumption by 2020.

FORMER DEMOCRATIC SOUTH CAROLINA SEN. JOHN EDWARDS: "We need investments in renewable energy -- more efficient cars and trucks -- and a national cap on carbon emissions." Supports at least 80 percent cut in carbon emissions by 2050, 55 mile-per-gallon fuel efficiency standard by 2030, 20 percent reduction in energy consumption by 2020.

FORMER REPUBLICAN NEW YORK MAYOR RUDY GIULIANI: "Climate change is real. It's happening. I believe human beings are contributing to it." No articulated position on carbon caps, fuel efficiency or energy use, but said he believes best way to deal with problem is through energy independence.

FORMER REPUBLICAN ARKANSAS GOV. MIKE HUCKABEE: "It's a spiritual issue. (The Earth) belongs to God. I have no right to destroy it." Backs an unspecified cap on carbon emissions and 35 mile-per-gallon fuel efficiency standard by 2020; favors alternative energy and energy independence.

REPUBLICAN ARIZONA SEN. JOHN MCCAIN: "I know that climate change is real ... we've got to address it, we can do it with technology, with cap and trade, with capitalist and free enterprise motivation." Co-authored bill to cut emissions by 65 percent by 2050, favors unspecified fuel efficiency increase and overall energy efficiency.

DEMOCRATIC ILLINOIS SEN. BARACK OBAMA: "For the sake of our security, our economy, our jobs and our planet, the age of oil must end in our time." Supports 80 percent cut in carbon emissions by 2050, 50 mile-per-gallon fuel efficiency standard in 18 years and 50 percent cut in energy intensity -- the amount of power used as it relates to economic growth product -- by 2030.

FORMER REPUBLICAN MASSACHUSETTS GOV. MITT ROMNEY: "Is global warming an issue for the world? Absolutely. Is it something we can deal with by becoming energy independent and energy secure? We sure can." Willing to consider carbon cap if it's enacted globally, opposes fuel efficiency standards as a stand-alone measure but generally supports fuel efficiency. (Reporting by Deborah Zabarenko, editing by Doina Chiacu)

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