Curbing contrails: A climate solution in the skies

Slowing down climate change is going to require big fixes, and many small ones, too. Case in point: contrails, those wispy white lines that trail some airplanes flying high in the sky. Contrails, short for condensation trails, are produced when exhaust from jets mixes with water vapor at extremely high altitudes, forming minuscule ice particles. Scientists have known for decades that in some cases, contrails spread out across huge areas, trapping heat in the atmosphere. That may sound insignificant given the vastness of the sky. Yet studies have estimated that contrails are responsible for as much as 35% of all of the planetary warming attributable to aviation. By some measures, contrails account for upward of 1% of human-caused global warming. “We now know enough about contrails and their impact to know we need to do something about it,” said Andrew Chen of RMI, a nonprofit that promotes sustainability. Here’s the new part: A team from Google, Breakthrough Energy and American Airlines says it has demonstrated a relatively cheap and easy way to significantly reduce contrails. Their research, which was shared exclusively with Climate Forward before being submitted to a scientific journal, found that adjusting a plane’s altitude by just a couple thousand feet reduced contrail formation by more than half. The results, they say, suggest it could be relatively easy, quick and cheap to start reducing contrails at scale. “The opportunity here is twofold,” said Chen, who was not involved in the project. “It’s near-term, and it’s cost-effective.”<br/>