.....with global warming? How about global dimming?

PBS's Nova had a fasinating report (and a fantastic website with a full report on the story) the other night on a proven phenomena called global dimming. The report starts with the observation by a meterologist on Sept. 12, 2001. On this day, he noticed that the sky seemed unusually bright and crystal clear and wondered why? Seeking the answer, he asked himself what was unusual about that day?

Well, of course this was the day after 911. A very distinctive component of that particular day was that there were no airplanes flying ...... anywhere. This observation led to an investigation of the effect of aircraft "contrails" on the brightness of the sun, specifically on dimming the brightness of sunlight. It turns out that these vapor trails from jets lead to significant reflection of sunlight back into space. The report further verifies through various studies that indeed, particulate pollution of all types has significantly impacted the amount of sunlight actually reaching the earth's surface, up to 30% in some areas of the globe. This loss of sunlight has resulted in a cooling of the earth's surface.

In light of the fact of global warming, this sounds like it might not be too bad, eh?

Scientist now believe, and have proven, that the net impact of global dimming and global warming has been a masking effect. In essence, global warming, alone, has been progressing much faster than previously thought while this effect has been masked by the less strong counter-effect of global dimming.

And here's the kicker.

Ironically we're getting much better at controlling the emissions of pollutants the cause global dimming, thus more warmth is reaching the earth. (cue the crisis music) This means the the impact of global warming is likely to accelerate as we improve pollution control. And the anticipated acceleration is at an alarming rate.


Swell.

If you'd like the complete scientific rundown on the proof of global dimming, visit the PBS website for the various studies that have been able to verify it's existence via some very good historical records. And of course, if you interested, you can buy a DVD of the program or watch it in reruns.