As mines close, they leave behind a troubling legacy: leaking methane. Methane is a greenhouse gas, about 80 times more potent than carbon dioxide. In November, over 100 countries committed to taking the problem more seriously, pledging to cut methane emissions 30 percent by 2030. North Fork Valley entrepreneur Chris Caskey is already a step ahead, using his business, Delta Brick and Climate Company, to address methane emissions while tackling other environmental problems. For Rocky Mountain Community Radio’s series on fossil fuel transition, KVNF’s Stephanie Maltarich reports.