Putting Carbon Back In Soil Could Help Fight Against Climate Change, Researcher Argues

Oct 25, 2019

Soil is the largest terrestrial carbon pool, accounting for over three times more carbon than all plants on earth. According to a researcher who specializes in environmental issues, this could make it a key tool in the fight against climate change.

Usually soil below the surface is the highest in organic carbon because the carbon is put into the soil by plant roots. Soils high in organic carbon look dark brown and crumbly (like a good cake).
Credit Soil Science / Creative Commons Attribution 2.0 Generic

“The soil stores three or four times as much carbon as the atmosphere contains,” said Dr. Rob Jackson, a professor at Stanford University who recently lectured at Utah State University. “The things we do to alter our soils, and especially to lose organic matter through agricultural practices, have released a lot of carbon to the atmosphere. They also provide an opportunity to restore that carbon.”

According to research by the International Soil Resource Center, human agriculture has caused the loss of 130 billion tons of carbon from soils globally. Soil carbon can be lost when the carbon is exposed to the air, allowing microbes to break it down. Ploughing is a major culprit, but Jackson thinks with the proper incentives, soil carbon could be restored.

“A really important role for soils in climate change is to restore carbon that’s been lost through ploughing and other practices," he said. "One thing we can do that is already done in some places is to provide incentives to take land out of ploughing. Western Canada, for example, has had programs to actively pay farmers to put carbon back into the soil through multi-cropping, nitrogen-fixers and fallow programs. So there are places in the world where these incentives are already happening.”

The benefits of restoring soil carbon don’t just extend to fighting global warming. Soils high in organic carbon are better for agriculture. They need less irrigation and fertilization because they hold more water, nitrogen and phosphorus. And they seem to prevent erosion because their granular structure keeps soil from being blown away.

“It’s not just about restoring carbon as an element. Restore soil carbon and we gain multiple benefits,” Jackson said.