American farmers earned nearly $6 million dollars for a year’s worth of carbon credits sold on the Chicago Climate Exchange. The National Farmers Union has just mailed out the checks to farmers—including four in Kentucky who earned more than $20,000. To participate in the carbon credit program, farmers agree to certain farming practices that capture more carbon dioxide, which is a greenhouse gas, in the soil. They can use a low-impact farming method called no-till or convert acres to grass. Farmers Union president Tom Buis says there are two other ways farmers can participate.“Forestry projects, which capture a lot more carbon from the air, and methane digesters, where you turn livestock waste into energy and capture the carbon," says Buis.Buis says the Farmers Union then sells their aggregated tons of carbon as credits on the Chicago Climate Exchange. And companies wanting to offset their own pollution buy them. This past year, farmers enrolled nearly 3 million acres in the program, keeping enough carbon dioxide stored in the soil to offset the yearly emissions of 320,000 automobiles.