More On Aircraft Pollution

Contrails, those wispy white condensation trails that form behind airplanes, may seem harmless enough. Yet astronomers say they are one more problem making it harder for them to use their telescopes. While some contrails dissipate quickly, others can persist or even develop into high-level cirrus clouds. “We know from satellite imagery that clusters of contrails can last for two days,” Danish astronomer Holger Pederson told BBC News. “If carried by the upper jet stream through the troposphere, they can travel hundreds of kilometers.” Contrail proliferation, combined with the effect of a warmer and cloudier climate, could make ground-based astronomy impossible within 40 years, the experts told BBC. If that’s not adequately guilt-inducing, “Flying kills,” according to George Monbiot, a columnist for The (U.K.) Guardian. “We all know it, and we all do it.” Airplane emissions hasten global warming, Monbiot says, and most airline travel is unnecessary and an indulgence of the wealthy. “Some 92 million Bangladeshis could be driven out of their homes this century [by rising sea levels], in order that we can still go shopping in New York,” he wrote.