Transportation
The Surprising Way Airplanes May Be Heating Up the World's Climate
Tantalizing evidence suggests that yes, air traffic is helping give the atmosphere a fever.
When looking for evidence of humanity's hand in climate change, it's easy to spot the belchers of greenhouse gases sitting at eye level: snaking rivers of bumper-to-bumper cars, say, or vapor-shrouded smokestacks at power plants.
Few people tend to look straight up, though, which if you had done it last Friday would've yielded a jittering mess of billowy streaks: