Global Warming Caused by Airplane Contrails Poised to Increase, New Study Says
By Jan Wesner Childs | Weather.com
At a Glance
- Previous research showed how contrails, which are similar to cirrus clouds, trap heat.
- Air travel was predicted to quadruple over a 44-year period starting in 2006.
- The effects of contrails on global warming are expected to triple.
While scientists and environmentalists have long called for curbs on carbon dioxide emissions from commercial airliners, new research has uncovered a potentially bigger environmental impact of air travel.
The amount of warmer air added to the atmosphere thanks to contrails, those white plumes often seen as jetliners stream across the sky, could triple by 2050, a study released this week in the journal Atmospheric Chemistry and Physics found.
The study expanded on previous research that showed how contrails, which are similar to cirrus clouds, trap heat. Other research has also concluded that the warm air trapped by contrails has a greater negative effect on global warming than carbon dioxide emitted by airplanes.
“Contrail cirrus’ main impact is that of warming the higher atmosphere at air traffic levels and changing natural cloudiness,” Ulrike Burkhardt, a co-author of the latest study and an atmospheric scientist at DLR, the German Aerospace Center, said in a press release.
Contrails are also a popular target among conspiracy theorists, who claim they are used by the U.S. government to drop harmful chemicals on unsuspecting citizens. That theory has been debunked repeatedly, including in extensive research by a group of Harvard scientists.
Lisa Bock, another author of the new contrail study and also a researcher at DLR, noted that contrails should be a factor in international anti-pollution agreements like Corsia, a United Nations plan to decrease air traffic carbon emissions.
“It is important to recognise (sic) 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,” Bock said in the press release.
Bock and Burkhardt analyzed air traffic data from 2006 that had been used in one of the previous studies, along with climate models to predict the future impact of contrails. They concluded that air traffic would quadruple by 2050, and thus lead to increased contrails. They said the impact would be greatest over North America and Europe.
The U.S. Federal Aviation Administration alone currently tracks more than 44,000 commercial flights daily, serving some 2.7 million passengers.
Bock added that further research is needed to fully understand the effects of contrails on climate change.
“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,” she said. “But it’s clear they warm the atmosphere.”