- Institut für Physik der Atmosphäre et al.
Scientists have suspected for a while that contrails, the frozen-vapor tubes created by airplane engines that nutsos call "chemtrails," play some role in anthropogenic global warming. The theory is that jets are basically birthing new cirrus clouds, and clouds have a known effect on weather: They hold in heat during the night and thin out the sunlight that hits the earth's surface during the day.
Now there's new data to back up the contrail connection.
Researchers from NOAA, Germany's Institut für Physik der Atmosphäre and other institutions probed 14 contrails left behind by nine different types of aircraft, including "the largest operating passenger aircraft" (presumably an Airbus A380). They concluded that contrails do indeed increase the temperatures on earth by trapping in heat, if only very slightly. However, they also warn that an expected doubling of air traffic over the next two decades will make the effect more pronounced. The FAA predicts that 1 billion U.S. citizens will take to the skies in 2021.
The solution? Go back to blimps. No, actually there is no great fix for this right now. That's why the scientists are recommending that more research be done on the poorly-understood phenomenon. You can read more about the methodology used in the study at the American Geophysical Union.