Study: Carbon-Rich Soil Could Contribute To Climate Change

Well below the soil depth of most home gardens, Wisconsin scientists say there might be more soil that is rich in carbon, and a new study suggests that could mean bad things for climate change.

Many scientists used to think most of the carbon in soil was only in the first half-meter of ground, but University of Wisconsin-Madison researchers working on land in Nebraska first ripped open by a road construction project have examined core samples taken from several meters underground .

UW geography Professor Erika Marin-Spiotta said she and her team found plenty of carbon in this soil.

“Usually, we have seen very little carbon, maybe even undetectable carbon at six meters below the surface. But, in this soil, we’re finding similar amounts of carbon that you’d find in the top meter of the soil,” she said.

The theory is the buried carbon was created long ago when glaciers retreated in the northern hemisphere, vegetation changed and wildfires occurred. Windblown silt or dust — known as loess — has since covered the carbon-rich soil in Nebraska.

But, Marin-Spiotta said that organic carbon in buried soils might be widespread and land developers may want to take that into account.

“You could decide to disturb or convert the piece of land that has less carbon in the soil, and that would be less vulnerable to be converted into carbon dioxide. And then, maybe think about ways that you could prevent further disturbance and exposure of this (soil),” she said.

Marin-Spiotta said the burning of fossil fuels in cars or power plants is the bigger source of greenhouse gases, but exposing carbon-rich deep soils might contribute to the problem of climate change.

The new UW study was reported in the journal Nature Geoscience.