Plants save the earth from an icy doom

While the upper limit for atmospheric CO2 levels has been a focus for discussions of global warming and the quality of life on Earth, this study points to the dynamics that maintain the lower sustainable limits of atmospheric CO2.

		IMAGE: As plants become starved for CO2, rock weathering diminishes. Click here for more information.

Volcanic gases naturally add CO2 to the atmosphere, and over millions of years CO2 is removed by the weathering of silica-based rocks like granite and then locked up in carbonates on the floor of the world's oceans. The more these rocks are weathered, the more CO2 is removed from the atmosphere.