On a Midwestern farm growing corn and beans, a tractor will soon spread 1,543 tons of rock dust over 140 acres. The goal: fighting climate change. Over the next two growing seasons, the dust — crushed basalt — is expected to capture 384 tons of carbon on the farm while helping crops grow. The farm is one of 14 that are working with Lithos, a new startup pioneering an unusual approach to carbon capture. Instead of pulling carbon dioxide from the air, when rain falls, it combines with atmospheric carbon dioxide to make it slightly acidic, and when the combination hits certain kinds of rocks, it causes a chemical reaction that slowly removes carbon dioxide from the atmosphere. Chris Reinhard, associate professor in the School of Earth and Atmospheric Sciences, is a Lithos cofounder. (This story is also covered in GeekWire and Carbon Herald.)