Compost and Grasslands with Whendee Silver

By Jericho Rajninger

Carbon sequestration is the process of capturing and storing atmospheric carbon dioxide to slow the pace of climate change. There are two major types of carbon sequestration: geologic and biologic. Geological carbon sequestration injects carbon dioxide captured from an industrial or energy-related source into underground geologic formations. Biological carbon sequestration refers to the storage of atmospheric carbon in vegetation, soils, woody products, and aquatic environments1. While carbon dioxide (CO2) is naturally captured from the atmosphere through biological, chemical, and physical processes, some artificial sequestration techniques exploit the natural processes to slow the atmospheric accumulation of CO2.

Soil Carbon Sequestration and Climate Change

The exchange of carbon between soils and the atmosphere is a significant part of the world’s carbon cycle. Carbon, as it relates to the organic matter of soils, is a major component of soil and catchment health. However, human activities including agriculture have caused massive losses of soil organic carbon, leading to soil deterioration.

Soil carbon sequestration is a process in which CO2 is removed from the atmosphere, primarily mediated by plants through photosynthesis, with carbon stored in the form of soil organic matter. Many scientists agree that regenerative agricultural practices can reduce atmospheric CO2 while also boosting soil productivity and health and increasing resilience to floods and drought.

UC Berkeley researchers found that low-tech agricultural management practices such as planting cover crops, optimizing grazing and sowing legumes on rangelands, if instituted globally, could capture enough carbon from the atmosphere and store it in the soil to reduce global temperatures 0.26 degrees Celsius – nearly half a degree Fahrenheit – by 2100. Improving soil quality through these techniques, therefore, can make a significant contribution to international global warming targets.

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Organizations

1 https://www.usgs.gov/faqs/what-s-difference-between-geologic-and-biologic-carbon-sequestration?qt-news_science_products=0#qt-news_science_products


Transcript

Ethan: How can grasslands help solve climate change? This is Ethan Elkind of Climate Break. The answer is dirt, and efforts to put carbon that would’ve ended up in the air, into soil on farms and ranches. Dr. Whendee Silver is a biogeochemist at UC Berkeley. A few years ago she began looking at grasslands, and she found that they’re running carbon deficits. 

Dr. Silver: If you look at the ecosystems globally that are managed that store the most carbon, it’s grasslands. And most of the grasslands globally are degraded with regard to their carbon, but it was like a bathtub that was half full that maybe we could start to fill up again.

Ethan: And where to find that excess carbon to inject into the soil? Easy: your compost bin. Silver works with California ranchers to divert food waste to grasslands… and the early research is exciting. 

Dr. Silver: We found that if you combined all the practices that we know sequester carbon in soils, we could technically lower global temperatures by about 0.3 degrees Celsius, and that doesn’t seem like much, but if you think we’ve already warmed one degree and we’re trying to keep it to 1.5, if we can get 0.3, that’s 60% of the way there.

Ethan: To learn more about Silver’s work and for more climate solutions, go to climatebreak.org or wherever you get your podcast.

Compost and Grasslands with Whendee Silver