This Startup Uses Volcanic Rock Dust to Capture Carbon on Farms
An ag-tech startup is spreading basalt rock dust on farmers’ fields as both fertilizer and an ingenious way to not only capture carbon, but remove it from the global carbon cycle forever.
At its maximum output, 3 tons of rock dust can capture 1 ton of CO2, a return on investment that if done at scale has an almost unlimited ceiling of carbon removal.
The business model is based on a mutually-beneficial exchange: the farmer’s fields are enriched with iron, phosphorus, magnesium, and calcium, boosting yields compared to agricultural limestone dust by 47% in some cases. The company, Lithos Carbon, sells the dust application as carbon credits to industries looking to offset their emissions, and gives a cut to the farmers.
“My approach to this is, if you can give farmers something that they will want and love and need, then they will do that,” Lithos CEO Mary Yap told Fast Company. “And then you will scale carbon capture almost as a side effect. One of my farmers has said, ‘I can’t eat carbon credits.’ Really, the crops at the end of the day are the thing that matters.”
The way the carbon is captured comes from one of the fundamental steps in the global carbon cycle. CO2 in the air is partially absorbed by rains, which deposit it into the soil and the oceans. When rains fall on a field treated with basalt rock dust from Lithos, the carbon is captured in the basalt, before the material is washed down rivers into the ocean.
Once in the ocean it’s taken up by a large variety of animals, often mollusks are other animals who use it to make their shells. Once they die, their shells fall to the ocean floor where the carbon remains, under most circumstances, permanently.
Basalt rock is the most common volcanic rock available on Earth and is produced by the millions of tons per annum in the mining industry, effectively guaranteeing a supply.
The primary challenge comes from the fact that every field will be different in how much dust is used and how it’s applied. Too much can released CO2 or be toxic to breathe in. For that they’ve developed intelligent software alongside Yale University.
At the moment Lithos is managing 14 farms, the most recent of which saw 1,500 tons of rust over 140 acres that should absorb 384 tons of CO2.