GAO study links aircraft emissions to global warming

Report says jet exhaust accounts for a "potentially significant and growing" portion of greenhouse gases.

provided by House Committee on Transportation and Infrastructure

new report from the General Accounting Office indicates that commercial jet aviation makes a significant contribution to the problem of global warming. The study further warns that emissions of carbon dioxide and other greenhouse gases can be expected to increase as commercial jet travel continues to grow worldwide.

The report was released by Rep. James L. Oberstar (Minn.), Ranking Democratic Member of the House Committee on Transportation and Infrastructure. The GAO study was done at Ober-star's request.

In his request, Oberstar pointed out that aviation is the fastest-growing segment of the transportation industry, growing at a rate of some five percent annually, and this has brought with it an increasing concern over aviation's impact on the environment.

"On the one hand, the industry's growth has created concerns about noise, air, and water pollution. On the other hand, environmental concerns have increased the time and cost of development and imposed restrictions on flight patterns, airport use, and airport capacity," Oberstar wrote.

The GAO found that, in the United States, aviation emissions accounted for about three percent of the greenhouse gases and other emissions that contribute to the global warming phenomenon. While this percentage is small in relative terms -- other transportation sources contribute 23 percent, and other industrial emissions account for 41 percent -- aviation emissions are potentially significant for a number of reasons:

  • Jet aircraft emissions are deposited directly into the upper atmosphere and some of them have a greater warming effect than gases emitted closer to the surface, such as automobile exhaust.
  • The primary gas emitted by jet aircraft engines is carbon dioxide, which can survive in the atmosphere up to 100 years.
  • Carbon dioxide, combined with other exhaust gases and particulates emitted from jet engines, could have two to four times as great an impact on the atmosphere as carbon dioxide emissions alone.
  • The growing demand for jet air service is likely to generate more emissions that cannot be offset by reductions achieved through technological improvements alone.
  • The report recommended further research into the impact of jet exhaust on the global atmosphere to help guide the development of new aircraft engine technology. It also called upon governments to reduce emissions through improved air traffic control and regulatory and economic incentives.

The report released today is the first in a series of studies on the environmental impact of aviation stemming from Oberstar's request.

Text of the report (GAO/RCED-00-57) is available on line at

Contact: Jim Berard, Democratic Director of Communications, House Committee on Transportation and Infrastructure, 2167-A Rayburn House Office Building, Washington, DC. 20515-6256; (202) 225-6260