Greenhouse Gases at Highest Levels in 650,000 Years

Scientists working in Antarctica have confirmed that levels of key greenhouse gases that contribute to global warming are higher today than at any time in the past 650,000 years—and humans are responsible for the increase.

The new research was published only days before representatives from 189 nations convened in Montreal for a major international conference on global warming to consider how to proceed when provisions of the Kyoto Protocol end in 2012.