Climate impact of traffic

Changes of the zonal ozone concentration in the atmosphere (in percent) by the air traffic in July 1990 as simulated using the global climate-chemistry model ECHAM/CH

At the Institute of Atmospheric Physics we investigate the effects of various transport emissions on the constitution of the atmosphere and the climate. For example, the relative contributions of single transport means (surface transport, navigation and aviation) are quantified. For this we use laboratory studies, airborne measurements in the atmosphere with the research aircraft HALO and Falcon, as well as global climate simulations, in particular with the climate-chemistry-model EMAC.

Transport emissions affect the environment in different ways. In addition to the greenhouse gas transport emits carbon dioxide (CO2), aerosol particles (e.g. soot and organic substances) as well as gases such as sulphur dioxide (SO2), nitrogen oxides (NOx) and hydrocarbons, which are partly converted to particulate matter. Particles impair the air quality and influence the climate by direct interactions with the solar radiation and indirectly by affecting the properties of clouds. A direct influence on clouds is exerted by air traffic though condensation trails. Furthermore, the emissions of nitrogen oxides, carbon monoxide and hydrocarbons cause an increase of the health and climate relevant gas ozone while the methane concentrations is decreased.

The influence of surface transport decreases with height, but air traffic influences the atmosphere in the flight levels, that is in about 12 km height. Emissions from ships increase the air pollution over the oceans. Here they are the only local source and therefore play an important role.