Oct. 13 (Bloomberg) -- Republican presidential candidate Mike Huckabee said he supports a mandatory cap on global-warming pollution and that the U.S. has a moral obligation to address climate change.

``It goes to the moral issue,'' the former Arkansas governor said at a climate-change conference today in Manchester, New Hampshire. ``We have a responsibility to reduce greenhouse-gas emissions, to conserve energy, to find alternative forms of energy that are renewable and sustainable and environmentally friendly.''

Huckabee said he supports an economy-wide ``cap-and-trade'' system to control greenhouse gases, which scientists say are causing climate change. The program, which has been introduced in Congress, would create a market for buying and selling permits to allow carbon-dioxide emissions. President George W. Bush is among Republicans who oppose a carbon cap.

``I was impressed,'' said Larry Schweiger, head of the National Wildlife Federation. ``He's only the second Republican candidate to say he supports cap-and-trade, which we believe is the real critical part of any effort to stop global warming.''

Republican Senator John McCain of Arizona also is calling for a federal limit on carbon emissions and is co-author of the bill in Congress.

To contact the reporter on this story: Kim Chipman in Manchester, New Hampshire at kchipman@bloomberg.net

Last Updated: October 13, 2007 18:10 EDT