by Miro Korenha and Alexandra Patel
Airplane contrails have long been the subject of a variety of exuberant conspiracy theories, including that of governments spraying toxic chemicals into the air to induce mass sterilization and mind control. Though you shouldn’t pay attention to most of the conspiracy theories, there are real dangers associated with trails of airplane engine exhaust. According to a study in the Atmospheric Chemistry and Physics journal, contrails exacerbate climate change by trapping heat that radiates from the Earth’s surface.
What’s Happening?: Contrails form when water vapor in the air latches on to the soot particles in airplane engine exhaust and can only form at high altitudes. While low-level clouds have a net cooling effect, contrail-formed clouds contribute to warming. As air traffic increases in the foreseeable future, the global warming effect of the aviation industry is predicted to triple by 2050. With new technologies, airplanes are also expected to reach higher altitudes, thus increasing the frequency in which contrails are formed.
By the Numbers:
– In just 2005, aviation already accounted for 5 percent of global warming, with the effect of contrails being the largest contributor.
– A 2011 study suggested that the net effect of contrail clouds contributes more to atmospheric warming than all the carbon dioxide (CO2) produced by planes since the dawn of aviation.
Why This Matters: According to a scenario tested during the study, a 50% reduction in airplane soot emissions could result in a 15% decrease in the warming effect of contrails. This can be done by bringing about changes in the type of jet fuel that is used in favor of more efficient and environmentally friendly alternatives. Unfortunately, in the United States, we’re falling short of this goal as GHG emissions from our air travel increased by 3.4% in 2018. Technology will have to advance, such as in the case of greener jet fuel, but in the meantime, we should all take steps to either limit our air travel or make it as sustainable as possible when we do have to travel.
Go Deeper: Read this piece going around green Twitter called, We Have to Stop Meeting Like This: The Climate Cost of Conferences. It’s also the reason why teen climate activist Greta Thunberg is sailing to UN Climate Action Summit in New York.