Methane emissions rising

After rising during the 1980s, the growth of methane in the atmosphere slowed during the 1990s, providing a bright spot in an otherwise gloomy global warming forecast.

And while methane concentrations in Earth's atmosphere have remained stable, the study suggests the news isn't as good as scientists once thought.

Writing in tomorrow's issue of the journal Nature, researchers say that human-caused methane emissions began rising again in 1999, possibly tied to China's booming economy.

The increase has been masked, however, by a drop in methane emissions from wetlands as they dried out, especially in the Northern Hemisphere and possibly due to global warming.