Planes are having a bigger impact on global warming than we thought

Vapour streaming from the back of a plane is a common sight which is synonymous with international travel but its impact on the environment could be disastrous. 

A study has found the impact of jet contrails will triple by 2050, with Britain set to be the biggest contributor. 

Air travel is becoming increasingly popular but the pretty trails act as a blanket on the world and trap in heat. 

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Contrails are produced by planes when their exhaust fumes mix with the air which form cirrus clouds which perform phenomenon known as radiative forcing. They contribute to global warming and this will triple by 205, a study claims (stock)

Air traffic is set to quadruple by 2050 and routes favouring higher altitudes will cause contrails to form in the tropics.   

But the impact on climate due to the icy clouds will be strongest over Britain, the US and the rest of Europe as they are the busiest air traffic areas in the world. 

Contrails form when the water vapour from the plane’s exhaust mixes with the air outside and condenses and freezes.  

They eventually form ‘cirrus clouds’ which contribute to global warming as they reflect less sunlight, trapping more on the surface, in a phenomenon known as ‘radiative forcing’.

In 2005, air traffic made up about five percent of all man made radiative forcing – with contrails being the largest contributor to aviation’s influence. 

But the threat they pose to the environment has been largely neglected in schemes to offset aviation emissions.

This is despite contrails contributing more to global warming than all CO2 emitted by aircraft since the start of aviation.

Lead author Dr Lisa Bock, of the Institute of Atmospheric Physics, Bavaria, said: ‘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 like the Corsia agreement.’

The Corsia arrangement was set up by the United Nations (UN) to tackle CO2 emissions from the aeronautics sector.

It hopes to offset all carbon emissions from 2020 but does not mention the damage caused by contrails.  

The study, published in Atmospheric Chemistry and Physics, states contrails can no longer be ignored.  

Air traffic is set to quadruple by 2050 and routes favouring higher altitudes will cause contrails to form in the tropics. But the impact on climate due to the icy clouds will be strongest over Britain, the US and the rest of Europe as they are the busiest air traffic areas in the world (stock)

Dr Bock and lab colleague Dr Ulrike Burkhardt predict contrails o rise in impact faster than the rise in CO2 radiative forcing because of pre-existing measures to increase fuel efficiency.  

But exactly how large their effect on surface temperature and possibly on rain and snowfall due to the cloud modifications is unclear, says Dr Burkhardt.

Added Dr Bock: ‘There are still some uncertainties regarding the overall climate impact of contrail cirrus and in particular their impact on surface temperatures because contrail cirrus themselves and their effects on the surface are ongoing topics of research. But it is clear they warm the atmosphere.’

One potential way of reducing the impact of contrail is preventing them from forming in the first place. 

This can be done by cutting the soot thrown out the exhausts which encourages them to form.  

But, this will likely prove ineffective, the researchers claim, and would not be sufficient to limit warming to 2005 levels.  

Rerouting flights to avoid regions particularly sensitive to the effects of contrail formation has also been suggested.