Earth's Carbon Can Be Stored in 'Deep' Soil.

• Position: GLOBAL WARMING

One-fourth of the carbon held by soil is bound to minerals as far as six feet below the surface, report research scientists at Washington State University, Vancouver, and the University of California, Santa Barbara. The discovery opens a new possibility for dealing with the element as it continues to warm the Earth's atmosphere.

There is one hitch, though: most of that carbon is concentrated deep beneath the world's wet forests, and they will not sequester as much as global temperatures continue to rise.

Marc Kramer, WSU associate professor of environmental chemistry and Oliver Chadwick, UC soil scientist, drew on new data from soils around the world to describe how water dissolves organic carbon and takes it deep into the soil, where it physically and chemically is bound to minerals. They estimate that this pathway is retaining about 600,000,000,000 metric tons, or gigatons, of carbon. That is more than twice the carbon added to the atmosphere since the dawn of the Industrial Revolution.

"We know less about the soils on Earth than we do about the surface of Mars," declares Kramer. "Before we can start thinking about storing carbon in the ground, we need to actually understand how it gets there and how likely it is to stick around. This finding highlights a major breakthrough in our understanding."

The scientists analyzed soils and climate data from the Americas, New Caledonia, Indonesia, and Europe, and drew from more than 65 sites...