Life-Cycle Vehicle CO2 Emissions

Life-cycle assessment tracks emissions generated and materials consumed for a product system over its entire life-cycle, from cradle to grave, including material production, product manufacture, product use, product maintenance and disposal at end of life. For vehicles, this includes the environmental burdens associated with making materials (e.g., steel, aluminum, brass, copper, various plastics, etc.), fabricating them into parts, assembling the parts into a vehicle, operating the vehicle over its entire lifetime, producing fuel for the vehicle, maintaining the vehicle and finally disposing of the vehicle at the end of its life. Life-cycle assessment is an essential tool in thinking about the environmental impacts of complex systems.

The table below details the results of a life-cycle analysis for a representative mid-size car and SUV in the United States. At present, life-cycle CO2 emissions from vehicles are dominated by CO2 released during fuel consumption. Product disposal has a minor impact on airborne emissions and energy consumption relative to other phases of the product system (approximately 2 percent). As vehicle fuel efficiency improves and lower carbon fuels are made available, the relative contributions of CO2 emissions from the fuel consumption phase will decrease.

Because many assumptions were required to generate such an analysis, many of which we have little or no control over, we do not expect to use the estimate as an ongoing performance measure. It did, however, enable us to better understand the total system's dynamics and the opportunities for reducing emissions.