U.S. greenhouse gas emissions headed back up again in 2007 as Americans used more energy to cope with a colder winter and warmer summer, according to an Energy Department report released today.

The European experience with carbon trading offers little concrete evidence of effectiveness but carries lessons for Congress in designing a U.S. carbon scheme, according to a new Government Accountability Office report.

A major environmental group and several companies teamed up today in releasing recommendations for U.S. EPA as it considers setting new global warming regulations.

President-elect Barack Obama faces monumental challenges if he is going to fulfill his promise of writing a "new chapter in America's leadership" on global warming. The Obama administration will face two unique and complicated rounds of negotiations -- writing a new international climate treaty and passing domestic cap-and-trade legislation -- that probably won't move at the same pace. It also must face high expectations after eight years of the Bush administration's pitched diplomatic battles on climate change strategies.

SAN FRANCISCO -- British Columbia's provincial government last week backed California's attempt to apply tough new carbon emissions standards to the auto industry.

European automakers must cut emissions of greenhouse gases from new vehicles by 18 percent within six years, the European Union agreed yesterday after a long battle between industry groups and environmentalists.

In a 984-foot tower in eastern Colorado, atmospheric scientist Arlyn Andrews checks to make sure narrow tubes running to analyzers nearby are properly taking continuous samples of carbon dioxide, methane and other greenhouse gases.