What is a contrail? What is their effect on climate change?
Condensation trails or “contrails” are the visible trails of water vapour sometimes left by aircraft as they fly. Contrails may in turn trigger the formation cirrus clouds. At present, no-one is entirely certain to what extent contrails and related clouds contribute to global warming. It is thought that contrails, by creating clouds, could trap outgoing radiation emitted by the Earth and atmosphere at a greater rate than they reflect incoming radiation from the sun. This could increase global warming. However, the effect varies daily and annually, and the overall extent of warming is not well known. Furthermore, it has even been suggested that cirrus clouds can sometimes cause global “cooling” and potentially slow the effects of climate change. Clearly, a better understanding is needed before formulating appropriate responses.
