Aviation emissions and climate impacts

Air traffic emissions contribute to climate warming in a very complex way. The emitted species alter the atmospheric composition and cloudiness, lead to changes in Earth’s radiation budget and finally contribute to human-made climate change. Major international crises have reduced the growth in emissions. However, air traffic and its emissions have grown over-proportionally after these crises. The non-CO₂ climate agents have a much shorter lifetime, which implies that the location and time, and also the meteorology at the time of emission, determine the lifetime of the perturbation. One of the most prominent climate impacts from aviation are contrails and the transition into cirrus, which here are referred to as “contrails”. A range of measures to reduce the climate impact from aviation has been discussed, which includes new technologies, alternative fuels, alternative routing and economic incentives. Emissions from air traffic contribute to climate change via a number of atmospheric processes which alter the abundances of so-called climate agents.