Worldwide CO2 emissions (This
Year) (1 ton = 2,000 lbs) 7,274,057,933 (tons)
U.S. Trees Cut Down (This Year): 334,978,306
Hot Trails TO FIGHT GLOBAL WARMING, KISS THE RED-EYE GOOD-BYE
BY CHRISTINA REED
Air travelers have more to hate about red-eye flights, where sleep is as ephemeral and satisfying as a bag of pretzels for dinner. Those overnight trips contribute more to atmospheric warming than daytime jetting.
Scientists have long known that airplane condensation trails act to both cool and heat the atmosphere. Formed by jet engines’ hot exhaust, contrails act as thin cloud barriers that not only refl ect sunlight but also
prevent the earth’s heat from escaping into space. During the day, the effect of blocked incoming radiation tends to outweigh that of trapped heat, thereby cooling the atmosphere. Indeed, after the events of 9/11 grounded all commercial U.S. fl ights for three days, daytime temperatures across the country rose slightly, whereas nighttime temperatures dropped. This evidence supported the hypothesis that contrails reduce
the temperature range by cooling the atmosphere during the day and heating it at night.
Thus, the timing of the flights is critical, but so is the atmosphere itself. Nicola Stuber of the University of Reading in England and her colleagues collected data from weather balloons over a region in southeastern England that lies within the North Atlantic flight corridor. Her team reported in the
June 15 Nature that even though fewer jets fly during the winter months, the season’s higher humidity makes these flights twice as likely to create contrails. The team also found that fl ying between 6 P.M. and 6 A.M. contributed between 60 and 80 percent of the climate warming that originated from contrails, even though these fl ights represent a quarter of the total air traffic.
Atmospheric scientist David Travis of the University of Wisconsin–Whitewater, who reported the 9/11-related contrail fi ndings, agrees with the British researchers that a reduction in nighttime flights is needed.
He adds that contrails “are currently a regional-scale problem but could eventually become a global-scale problem as air traffic continues to expand and increase.” Scientists are only beginning to study the contribution of jet exhaust to global warming, but so far, like red eyes, contrails don’t look
so good.
Air travelers have more to hate about red-eye flights, where sleep is as ephemeral and satisfying as a bag of pretzels for dinner. Those overnight trips contribute more to atmospheric warming than daytime jetting.