Spreading rock dust on the ground could pull carbon from the air, researchers say

From the article:

Known as enhanced rock weathering, the process involves layering crushed rock onto soil. When silicate or carbonate minerals in the dust dissolve in rain water, carbon dioxide is drawn from the atmosphere into the solution to form bicarbonate ions. The bicarbonate ions are eventually washed by runoff into the ocean, where they form carbonate minerals, storing their carbon indefinitely.

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The researchers say the cost of enhanced rock weatherization is comparable to other proposals to remove carbon dioxide, including sequestration, in which CO2 is captured as it is emitted from a power plant or a factory and is absorbed into a liquid or a solid and stored. But spreading rock dust over farmland carries the added benefit that it could help rebuild deteriorating agricultural soils in many parts of the world, they argue.

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Farmers have long applied limestone to their fields to reduce acidity and provide nutrients in Africa, Brazil and Malaysia. Enhanced rock weathering replaces lime with crushed calcium and magnesium-rich silicate rock.

Spreading volcanic rock on farmland not only has the potential to remove carbon dioxide but has several side benefits, the scientists said. The practice does not compete with the use of agricultural land — in fact, it can enhance the quality of the soil, improving crop yields while reducing the need for artificial fertilizers. Rock left over from mining or construction — “waste rock” — can be processed for this use, creating a reason to recycle it, the researchers said.

Here is the study.