Carbon dioxide is the predominant global warming pollutant, accounting for eighty percent of global warming emissions. Contrary to the goals set out in legislation recently considered in the U.S. Senate, emissions have continued to increase. Transportation is responsible for 32.3% of all carbon dioxide emissions in the U.S. While the U.S. has made progress in reducing vehicles' emissions of regulated pollutants such as ozone precursors, CO2 emissions from the transporatation sector continue to rise.
Growing U.S. Carbon Emissions
Source: EERE's Transportation Energy Data Book Ed. 24
The share of emissions produced by the transportation sector is expected to increase faster than emissions for the entire U.S. economy. According to the Energy Information Administration, transportation emissions are expected to increase by 1.8% per year while the residential and industrial sectors are expected to increase by only 1.2% and 1.0%, respectively.
Transportation's Share of U.S. Carbon Emissions Is Increasing
Source: EERE's Transportation Energy Data Book Ed. 24; 2025 projection from EIA's Annual Energy Outlook (2005)
Vehicle-Based Air Pollution
While new cars and trucks are far cleaner than their predecessors, motor vehicles remain the largest source of health-threatening air pollutants. To find out how much pollution current production vehicles emit, visit greenercars.org, the online home of ACEEE's Green Book®: The Environmental Guide to Cars and Trucks.