The contrails left by aeroplanes last only hours. But they are now so widespread that their warming effect is greater than that of all the carbon dioxide emitted by aeroplanes that has accumulated in the atmosphere since the first flight of the Wright brothers.
Worse still, this non-CO2 warming effect is set to triple by 2050, according to a study by Ulrike Burkhardt and Lisa Bock at the Institute of Atmospheric Physics in Germany.
Altogether, flying is responsible for around 5 per cent of global warming, the team says, so this figure will soar even higher – and no meaningful actions are being taken to prevent this.
