The industrial sector directly accounts for nearly 20 percent of total U.S. greenhouse gas emissions – these come from both energy (on-site combustion) and non-energy (industrial processes) sources. When greenhouse gas emissions from electricity use are distributed among end-use sectors, the industrial sector accounts for about 30 percent of total U.S. emissions. Industrial processes that produce greenhouse gas emissions vary significantly and include such diverse sources as iron and steel production, cement production, and the petrochemicals industry.

Transportation accounts for nearly 30 percent of total U.S. greenhouse gas emissions, which come primarily from the combustion of petroleum-based fuels. Most transportation emissions are from fuel use in one of four vehicle types: passenger cars, light-duty trucks (which include SUVs, pickup trucks, and mini-vans), heavy-duty vehicles, and airplanes.