New research shows that planes are contributing to global warming through the white, vapour trails they leave in the sky, research has found.
These trails are thin clouds of ice particles and soot and are threatening the environment as they act as ‘blankets’ trapping heat below them.
The white streaks do more damage to the climate than the carbon dioxide emitted by the aircrafts, experts suggest.
They warned the impact of the vapour trails will only get worse as air traffic is expected to quadruple by 2050.
The white streaks, also known as contrails, form high in the atmosphere when the water vapour in the plane’s exhaust condenses and freezes in the air.
They spread into extensive ‘cirrus clouds’ that help bake the planet because they reflect less sunlight.
But the threat they pose has been largely neglected in schemes to offset aircraft emissions, including the Carbon Offsetting and Reduction Scheme for International Aviation (Corsia) agreement.
Dr Lisa Bock, of the Institute of Atmospheric Physics in Germany, says: "It is important to recognise the significant impact of non-CO2 emissions, such as contrail cirrus, on climate and to take those effects into consideration when setting up emission trading systems or schemes such as the Corsia agreement."
Dr Bock added: "There are still some uncertainties regarding the overall climate impact of contrail cirrus... But it is clear they warm the atmosphere."
The study was published in The Journal Atmospheric Chemistry and Physics.