The Chevrolet division of General Motors purchased credits for a 40,000 ton reduction in carbon dioxide emissions from ranchland in the “prairie pothole” region of North Dakota. The purchase was announced during a news conference at USDA headquarters. Ducks Unlimited used a USDA grant to develop the methodology to quantify the carbon locked in the soil through an easement against converting the grassland to crops. Under this approach, ranch owners generate additional income while retaining access to range land. Chevrolet bought the credits as part of a plan to reduce carbon dioxide emissions by 8 million tons.