How Can Soil Reduce CO2 Levels?

Written By Teacher: Teresa Pettitt-Kenney

Hi there! My name is Teresa and I just finished my Bachelor's degree in Environmental Science and am excited to pursue environmental education in the future! I am extremely passionate about climate change, equitable climate action, and how education can work to address these issues. 

For students to have a well-rounded understanding of the carbon cycle and climate change, they need to learn about the various areas where CO2 is stored. Exploring carbon storage in soils can provide an in-depth study of carbon sinks and offer a uniquely exciting solution to our greenhouse gas problem. Keep the climate change discussion light and empowering by highlighting nature-based solutions using resources like this climate solutions video. Get more hands-on with outdoor observation and activities and allow students to make a physical and mental connection with what they are learning about.

Written By: MIT Environmental Solutions Initiative

The MIT Climate Change Engagement Program, a part of MIT Climate HQ, provides the public with nonpartisan, easy-to-understand, and scientifically-grounded information on climate change and its solutions.

Soils are made in part of broken-down plant matter. This means they contain a lot of carbon that those plants took in from the atmosphere while they were alive. Especially in colder climates where decomposition is slow, soils can store—or “sequester”—this carbon for a very long time. If not for soil, this carbon would return to the atmosphere as carbon dioxide (CO2), the main greenhouse gas causing climate change.

But converting natural ecosystems like forests and grasslands to farmland disturbs soil structure, releasing much of that stored carbon and contributing to climate change. Over the past 12,000 years, the growth of farmland has released about 110 billion metric tons of carbon from the top layer of soil—roughly equivalent to 80 years’ worth of present-day U.S. emissions. The question is: Can this trend be reversed at the global scale as part of a strategy to help fight climate change?

Storing carbon in agricultural soils

Scientists have estimated that soils—mostly, agricultural ones—could sequester over a billion additional tons of carbon each year. This has led policymakers to increasingly look to soil-based carbon sequestration as a “negative emissions” technology—that is, one that removes CO2 from the air and stores it somewhere it can’t easily escape.