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Climate impact of clouds made from airplane contrails may triple by 2050
In the right conditions, airplane contrails can linger in the sky as contrail cirrus—ice clouds that can trap heat inside the Earth's atmosphere. Their climate impact has been largely neglected in global schemes to offset aviation emissions, even though contrail cirrus have contributed more to warming the atmosphere than all CO2 emitted by aircraft since the start of aviation. A new study published in the European Geosciences Union (EGU) journal Atmospheric Chemistry and Physics has found that, due to air traffic activity, the climate impact of contrail cirrus will be even more significant in the future, tripling by 2050.
Contrail cirrus change global cloudiness, which creates an imbalance in the Earth's radiation budget—called 'radiative forcing' - that results in warming of the planet. The larger this radiative forcing, the more significant the climate impact. In 2005, air traffic made up about 5% of all anthropogenic radiative forcing, with contrail cirrus being the largest contributor to aviation's climate impact.
"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," says Lisa Bock, a researcher at DLR, the German Aerospace Center, and lead-author of the new study. Corsia, the UN's scheme to offset air traffic carbon emissions from 2020, ignores the non-CO2 climate impacts of aviation.
But the new Atmospheric Chemistry and Physics study shows these non-CO2 climate impacts cannot be neglected. Bock and her colleague Ulrike Burkhardt estimate that contrail cirrus radiative forcing will be 3 times larger in 2050 than in 2006. This increase is predicted to be faster than the rise in CO2 radiative forcing since expected fuel efficiency measures will reduce CO2 emissions.
Contrail cirrus radiative forcing for future air traffic (DOI: 10.5194/acp-19-8163-2019)
(Score: 2) by edIII on Saturday June 29 2019, @01:57AM (1 child)
This just doesn't make sense though at scale. I'm not seeing criss-crossing contrails covering the sky during the day. Size wise isn't this like a super thin hair being stretched out over a lake?
Meaning, a very tiny percentage of the sky (.01%) surely is what they're talking about right? That much difference in cloud cover can register on the scales of climate change? Compared to a cow "fart" how bad is it?
There must be a lot more contrails then I think, or the effect is exaggerated.
Technically, lunchtime is at any moment. It's just a wave function.
(Score: 1) by Sabriel on Saturday June 29 2019, @06:01AM
"In the right conditions, airplane contrails can linger in the sky as contrail cirrus—ice clouds"
Atmospheric water vapour can more easily condense in the presence of a catalyst (such as existing water droplets, ice crystals or dust, all of which are much more common at low altitudes). Clouds form when this effect is propagated across an area.
Aircraft contrails can sometimes trigger this cascade effect. Thus the name "contrail cirrus" - cirrus (high-altitude) clouds created by contrails.
So it's not the contrails themselves that directly impact climate, it's the resulting clouds that can form around them (which would otherwise not have happened).