U.S. Elections 2008 : Ron Paul – Global Warming View
Paul, according to Internet reports and blogs, is skeptical about climate change. In 2004, he voted against implementing the Bush administration’s national energy policy, which funded energy conservation and research and development on alternative energy sources.
Source: http://uspolitics.america.gov/uspolitics/elections/issues.html#15

U.S. Elections 2008 : Barack Obama – Global Warming View
Obama says the United States is responsible for leaving the planet in better shape for future generations. His plan would reduce greenhouse gas emissions, implement a market-based cap-and-trade system to reduce carbon emissions 80 percent by 2050, set a national standard for low-carbon fuels and increase [...]

U.S. Elections 2008 : John McCain – Global Warming View
McCain would limit carbon dioxide emissions by harnessing market forces to bring advanced technologies like nuclear energy to market faster, reduce dependence on foreign energy supplies and ensure that all nations contribute to the climate change solution. He was lead author of a Senate proposal to [...]

Mike Huckabee – U.S. Elections 2008 : Global Warming View
Huckabee proposes to explore, conserve and develop all forms of alternative energy to achieve U.S. energy independence. He would set a federal research and development budget that the private sector would match to seek the best new alternative fuel products.
Source: http://uspolitics.america.gov/uspolitics/elections/issues.html#15