How Compost Combats Climate Change

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During the dirty ‘30s, drought and overworked fields turned the southwestern plains into a giant dustbowl. Thousands of farmers were forced into bankruptcy; homes were buried to their roofs in dust; the government bought cattle for $1 a head to keep them from starving in abandoned, barren fields. Nearly a century later and we are still discovering the vital role soil plays in our interconnected environment. 

Dust Bowl Photo

We’ve learned soil is a ‘carbon sink’. Meaning, like old forests and oceans, healthy soil stores more carbon than it releases. Scientists say soil holds more carbon than the atmosphere, and all plant life combined! 

However, soil is also quick to release the carbon it holds when disturbed by tilling, pesticides, and over-farming. This is where compost comes in.

Compost and Carbon:

A recent 19-year study of compost use out of the University of California Davis shows that depleted soil treated with compost is able to retain carbon better and grabs more carbon dioxide from the air. And the soil continued to improve years after the first compost application. To combat climate change and our rapidly increasing carbon dioxide levels, experts agree that we’ll need to tap into the vast carbon sinks available in the world’s soils. 

“One reason we keep losing organic matter from soils is that our focus is on feeding the plant, and we forget the needs of others who provide important services in soil like building organic carbon,” says Kate Scow, director of the UC Davis Russell Ranch Sustainable Agriculture Facility. “We need to feed the soil, too.” 

Studies also show that carbon and hungry microbes contained in compost make soil more fertile. “Surprise!” said no one who’s ever used compost. SWALCO and the University of Illinois are currently conducting a two-year study to measure the effects of compost on local soil as part of a USDA grant. Those findings will be released in 2022.


Compost and Methane:

Compost also has a second climate fighting benefit— methane reduction. When organic waste like food and yard waste breaks down in a landfill, methane is created. Methane is a greenhouse gas 20 to 30 times more potent than carbon dioxide, and landfills are the 3rd largest contributor of methane in the U.S. By diverting food and organic waste away from landfills to make compost, less methane is released into the atmosphere.

So the next time you throw your coffee grounds and banana peels in your compost bin, realize you’re doing a lot more than saving waste, you’re also combating climate change. 

By Tracy Bugh, Civil Agents, for SWALCO

This material is based upon work supported by the U.S. Department of Agriculture, under agreement number NR203A750001C028. USDA is an equal opportunity provider and employer.