How rock dust is used to fertilize farms, clean the air

Yahoo

22-04-2025

A simple solution to making modern life more sustainable may have been hiding under our feet -- and bikes and cars and trunks -- this whole time.
A North Carolina-based carbon removal company has been collecting rock dust leftover from the construction of roadways, runways and roofs and using the nutrient dense material to capture carbon and make farming more efficient.
The rocks, such limestone and basalt -- as well as volcanic ash -- are found in nature, similar to other forms of natural carbon capture, such as trees in forests and seaweed underwater.
MORE: Mile-deep underwater volcano could erupt off West Coast this year, scientists say
Silicate minerals crushed in basalt can permanently remove carbon dioxide from the atmosphere -- a solution called enhanced rock weathering that Lithos Carbon has been using to transform farmland into carbon capture centers.
In the past, the rock dust would be thrown away and sent to landfills, but researchers have discovered it's actually a carbon sink and increases crop yields significantly. Lithos Carbon has been capturing up to 1 billion tons of carbon dioxide per year using the basalt dust, Mary Yap, CEO of Lithos Carbon, told ABC News.
"It's not rocket science," Yap said. "It's rock science."
Finding natural solutions to remove carbon from the atmosphere can offset the dozens of billions of emissions released into the atmosphere each year. In 2024, 37.4 billion metric tons of carbon dioxide was emitted globally — up from 11 billion tons released annually in the 1960s, according to the Global Carbon Budget.
The rocks are ground to a fine dust to speed up the carbon capture process. A large chunk of rock would take thousands of years to capture the same amount of carbon, Yap said.
"Our job is to supercharge what nature could do over time," Yap said.
The dust is then spread over millions of acres of land in a 1-millimeter depth. As the material is spread, data measured from the cab of the tractor is sent to Lithos, which collects soil samples to ensure their efforts are working.
MORE: Hawaii's Kilauea volcano, one of the world's most active, erupts for 7th time since December
Lithos Carbon's goal is to capture another billion tons of carbon over the next decade using the waste matter from the Sunrock mine, just outside Durham, North Carolina.
The miners have been stockpiling the waste for the past decade, ever since they discovered the rock dust is actually climate gold -- resulting in a 125-foot mountain of material. Lithos Carbon is now carting the rock dust away by the truckload to nearby farms.
Rick Bennett, a lifelong farmer in Butner, North Carolina, has been sprinkling the rock dust onto his fields as fertilizer and is now convinced that some things are not too good to be true, he told ABC News.
"The pH of the soil and increasing crop yields ... it also benefits every person on the planet -- that it's cleaning the air at the same time," Bennett said.
MORE: Food prices could increase further due to climate change's effect on inflation around the world: Study
Lithos is touting enhanced rock weathering as a straightforward and natural solution to the climate crisis and decarbonizing industries.
"We're just taking things humans already do -- rocks, farms, tractors, spreaders, science -- and then bringing it all together," Yap said. "And hopefully something that more of the globe can run with as well."
ABC News' Climate Unit contributed to this report.
How rock dust is used to fertilize farms, clean the air originally appeared on abcnews.go.com