DOT Center for Climate Change | About Transportation and Climate Change

Virtually all human activities have an impact on our environment, and transportation is no exception. While transportation is crucial to our economy and our personal lives, as a sector it is also a significant source of greenhouse gas emissions. The increase in atmospheric concentrations of greenhouse gases has been widely recognized by the scientific community as contributing to a gradual rise in global temperatures, resulting in various accompanying climatic disturbances.

illustration of a car, airplane and factory with smoke stacks
We need energy to do things like drive a car,
fly a plane, or make things in factories.
But we need to use energy wisely
if we want to help slow global warming.

Transportation contributes to global warming through the burning of gasoline and diesel fuel. Any process that burns fossil fuel releases carbon dioxide, a greenhouse gas, into the air. Based on global warming potential, carbon dioxide accounts for over 80 percent of total greenhouse gas emissions in the United States. In 1998, transportation sources accounted for approximately one quarter of total U.S. greenhouse gases emissions.

In contrast with trends in other air emissions, greenhouse gas emissions from transportation continue to rise, in large part because travel growth has outpaced improvements in vehicle energy efficiency.