Author: Bobby Magill
The earth’s soil stores a lot of carbon from the atmosphere, and managing it with the climate in mind may be an important part of reducing greenhouse gas emissions to curb global warming, according to a paper published Wednesday in the journal Nature.
“Climate-smart” soil management, primarily on land used for agriculture, can be part of an overall greenhouse gas reduction strategy that includes other efforts like carbon sequestration and reducing fossil fuel emissions, the paper’s authors said. Many scientists believe new efforts to reduce greenhouse gases in the atmosphere are needed to keep global warming to an internationally agreed-upon limit of 2°C (3.6°F).
“One way to do that is by locking up carbon in soils,” said study co-author Pete Smith, professor of soils and global change at the University of Aberdeen in Scotland. “If we can do this, we can complement efforts in other sectors to stabilize the climate and deliver on the Paris agreement.”
About three times the carbon currently in the atmosphere is stored in the Earth’s soil—up to 2.4 trillion metric tons, or roughly 240 times the amount of carbon dioxide emitted by burning fossil fuels annually.
Much of that is locked up in land used for agriculture. Cropland soil stores atmospheric carbon in organic matter such as manure, roots, fallen leaves and and other pieces of decomposing plants. It doesn’t remain there permanently. It takes decades for the organic matter in the soil to decompose, and the carbon stored within is eventually emitted back into the atmosphere as gas. Soil is responsible for 37 percent of global agricultural greenhouse gas emissions, according to the paper.