Plane Contrails Have a Surprising Effect on Global Warming The wispy ice clouds formed by jet exhaust help trap heat near the Earth's surface. WIRED is where tomorrow is realized. Tammi Reidl believes that to mitigate global warming, mysterious airplanes spray chemicals into the atmosphere to form sun-blocking artificial cloud cover. "And contrails are much more prevalent when the sun is out," he said. Airplanes emit gases (carbon dioxide, water vapour, nitrogen oxides or carbon monoxide − bonding with oxygen to become CO2 upon release) and atmospheric particulates (incompletely burned hydrocarbons, sulfur oxides, black carbon), interacting among themselves and with the a… Airlines are more conscious than ever about their image with regard to climate change—see the recent proclamations about going carbon-neutral from JetBlue and Delta—and this could make for an easy way to impress the public and help the planet. According to a recent study in Nature Climate Change, the radiative forcing, or warming, from aircraft contrails exceeds that of all CO2 emissions produced by the entire 113‑year history of aviation. Often, though, that saturation is confined to a narrow band of altitude, and airplanes can find drier areas by moving up or down. “There’s no mirror,” says Les Westbrooks, a professor of aeronautical science and airline operations at Embry-Riddle Aeronautical University. “There is speculation that even if you did not have soot coming out of the back of an aircraft engine, in many cases a contrail would still form.” That’s because That theory has been debunked repeatedly, including in extensive research by a group of Harvard scientists. Recent studies have found that contrails (a portmanteau of condensation and trails) may contribute as much as or more than all flights to the warming of the planet. 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. Stay in the know with our Transportation newsletter. Clouds trap heat coming off the earth that would otherwise head for space, making them the biggest variable in the planet’s temperature and climate, according to NASA. So as plane after plane runs the same route through the air, new and old contrails mingle and accumulate, forming airborne mosh pits of ice cloud. They said the impact would be greatest over North America and Europe. Hot humid air from the engine exhaust mixes with the colder surrounding air, causing the water vapor to condense into droplets or ice crystals that form visible clouds. Scientists are now warning that emissions from airplane engines are a grave threat to the world. The trends in cirrus cover and warming over the United States were greatest during winter and spring, the same seasons when contrails are most frequent. The effects of contrails on global warming are expected to triple. 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. Check out our Gear team’s picks for the. Shape memory alloys could make plane wings that flap, to reduce drag, or increase stability in supersonic flight. "But it’s clear they warm the atmosphere.". But … They can stretch tens of miles. While those conspiracy theories have been widely disproven, scientists say contrails' effect on global warming is not being seriously addressed. We've known that planes form contrails, or long, reflective clouds, since the end of World War I. The real issue – global warming caused by aircraft emissions – calls on us to act. They’re unlikely to want to jog up and down through the atmosphere, looking for a sweet spot. Most contrails last only a few minutes, but some spread and mix with other contrails and cirrus clouds, forming ‘contrail cirrus’ that linger for up to eighteen hours. Contrails, those white ribbons jets leave behind in the sky, will exacerbate global warming in the next few decades, a new study published Thursday suggests. The study expanded on previous research that showed how contrails, which are similar to cirrus clouds, trap heat. The better news, Stettler and his coauthors report, is that those planes can avoid making most contrails with minor altitude changes. The long, feathery lines of condensation that form behind aircraft, called contrails, have more of an immediate warming effect on the Earth's surface than the … Stettler suggests some sort of sensor on the plane, or having pilots alert each other when they see the white stuff. The researchers found that contrails have an overall warming effect, acting like a light blanket. He estimated that aviation contributed 4% to man-made global warming, with most of it from contrails rather than carbon dioxide and other greenhouse gases. “The contrails are trapping more heat in the atmosphere compared to cooling from reflected sunlight,” Spangenberg said. Air travel was predicted to quadruple over a 44-year period starting in 2006. They matched that to weather data and used a computer model that predicts when aircraft create contrails to see which flights would have done the most damage. But small changes in altitude can dampen the effect, a study says. Of the varied conspiracy theories regarding contrails—you know, chemtrails—one stands out for being especially wrong: the belief that the plane-made clouds are chemicals the government is secretly spraying to battle climate change, to the peril of those on the ground. How Winter Fashion Has Changed in 100 Years (PHOTOS), Eerie Vintage Photos of People Battling the Flu, Democratic Republic of the Congo | Français, State of Vatican City (Holy See) | Italiano. Previous research showed how contrails, which are similar to cirrus clouds, trap heat. Bock added that further research is needed to fully understand the effects of contrails on climate change. These results, along with findings from earlier studies, led to the conclusion that contrails caused the increase in cirrus clouds. Contrail clouds reflect heat back to Earth's surface which would otherwise have harmlessly drifted into space. According to Carleton, such a model could be used to re-route planes to prevent the formation of contrails, thereby limiting their impact on surface temperatures. Contrails are human-made clouds. Contrails found to impact climate change for a different reason. Ad Choices, Plane Contrails Have a Surprising Effect on Global Warming. One snag might be figuring out when a plane is leaving a cloud in its wake. But focusing on ‘chemtrails’ absolves people of the responsibility to do so At high altitudes the air is very cold. According to a January paper in the journal Environmental Science & Technology, the troublemakers are mostly flights that take off in the late afternoon and early evening, whose contrails live mostly during the night—when they still trap some heat but can’t deflect any sunshine (which can balance out their impact).