Did anyone watch the Horizon programme the other week, on Global Dimming? - I'll find a link in a minute - but basically they were saying that global dimming has been reducing the amount of sunlight that reaches the earth, and in effect cooling the earth down - they gave an example - Jet Contrails from airliners have often been believed to contribute to global dimming, but they'd never been able to prove it, however, after sept 11, when all jets stopped flying and the sky was clear for a few days, they found that the temperature leapt up bu a degree - and as soon as jets started flying again, the temperature dropped.
Now the theory is that pollutants in the air, i.e. soot etc, have been contributing to this global dimming, and as such, helping negate the effects of global warming, which they are now saying could be a lot worse than people actually originally thought...
Edit:
one link
Edit :
second link (the bbc! must be true!
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