4.2 Atmospheric Effects of Aviation Project (AEAP)

Aircraft engine emissions affect climate change in three ways that are expected to increase in concern as aviation grows:

• From the burning of fossil fuels, aircraft produce about 3 percent of annual global emissions of carbon dioxide (CO2), the most important greenhouse gas. There is good scientific understanding of the impact of these emissions, which is the same as for CO2 at the earth's surface, such as from autos or power plants.
• At high altitudes (25,000 to 50,000 feet), nitrogen oxide (NOx) emissions affect the production of ozone and the concentration of methane, both potent greenhouse gases for which a fair scientific understanding has developed.
• The third effect results from emissions of aerosol and particulate matter at high altitudes, and can be observed by the apparent increased incidence of cirrus clouds and the persistence of contrails, which influence the radiative character of the atmosphere. There is increasing knowledge about these effects, but poor scientific understanding.

The NASA Atmospheric Effects of Aviation Project (AEAP) conducts focused laboratory experiments, computer modeling, and field observations that support periodic assessments of aviation's impact on climate change. These assessments are being used as a basis for national and international policy. Most recently, AEAP was a major contributor to the Special Report on Aviation and Global Atmosphere by the Intergovernmental Panel on Climate Change.

NASA POC:
Richard J. Lawrence
301-286-1022
rlawrenc@pop400.gsfc.nasa.gov
http://hyperion.gsfc.nasa.gov/AEAP/