Moment of environmental apocalypse zen: airplane exhaust scars

Doug says,

"Some time back, one of the Boingers posted an article about the environmental effects of airplane traffic. To further support this article that may or may not exist, I submit today's Astonomy Picture of the Day that shows plane contrails like scars on the land. Link.

And a "contrail count for kids" program over the next two days: Link."

From an April, 2004 NASA press release about the environmental effects of plane exhaust:

NASA scientists have found that cirrus clouds, formed by contrails from aircraft engine exhaust, are capable of increasing average surface temperatures enough to account for a warming trend in the United States that occurred between 1975 and 1994.