[westmichman]

This is where I got the water vapor idea. Thought you might be interested. I was wrong, it's not water vapor but ice crystals that are the dirty little secret.
PING

[cogitator]

This particular idea has already been addressed here:

http://www.realclimate.org/index.php/archives/2006/03/meteors-nuclear-tests-and-global-warming/

Summary: the idea needs a lot more work.