On a banana plantation in rural Australia, a second-generation farming family spreads crushed volcanic rock between rows of ripening fruit. Eight thousand kilometers away, two young men in central India dust the same type of rock powder onto their dry-season rice paddy, while across the ocean, a farmer in Kenya sprinkles the powder by hand onto his potato plants. Far to the north in foggy Scotland, a plot of potatoes gets the same treatment, as do cattle pastures on sunny slopes in southern Brazil.
And from Michigan to Mississippi, farmers are scattering volcanic rock dust on their wheat, soy and corn fields with ag spreaders typically reserved for dispersing crushed limestone to adjust soil acidity.
Across six continents, these farmers are experimenting with a technique called enhanced rock weathering, designed to improve degraded soils and help save the planet from climate doom.
Enhanced rock weathering takes advantage of Earth’s natural carbon cycle, which keeps carbon dioxide in perpetual rotation between air, water and soil. Volcanic rock naturally traps atmospheric CO2 in a process that transforms the gas into a solid form. Like a thermostat, rock weathering can slowly moderate Earth’s temperatures over geologic time by keeping atmospheric levels of CO2, a greenhouse gas, in check.