Cheat-Seeking Missles

Monday, March 19, 2007

Is Global Warming Really Just Global Brightening?

Oh, it just gets complexer and complexer!

Now NASA tells us -- after nearly 30 years of attacking pollution -- that drops in pollution and global aerosols may actually be exacerbating temperature rise.
A new NASA study has found that an important counter-balance to the warming of our planet by greenhouse gases – sunlight blocked by dust, pollution and other aerosol particles – appears to have lost ground.

The thinning of Earth’s “sunscreen” of aerosols since the early 1990s could have given an extra push to the rise in global surface temperatures. The finding, published today in the journal Science, may lead to an improved understanding of recent climate change. ...

“When more sunlight can get through the atmosphere and warm Earth’s surface, you’re going to have an effect on climate and temperature,” said lead author Michael Mishchenko of NASA’s Goddard Institute for Space Studies (GISS), New York. “Knowing what aerosols are doing globally gives us an important missing piece of the big picture of the forces at work on climate.”

The study uses the longest uninterrupted satellite record of aerosols in the lower atmosphere, a unique set of global estimates funded by NASA. Scientists at GISS created the Global Aerosol Climatology Project by extracting a clear aerosol signal from satellite measurements originally designed to observe clouds and weather systems that date back to 1978. The resulting data show large, short-lived spikes in global aerosols caused by major volcanic eruptions in 1982 and 1991, but a gradual decline since about 1990. By 2005, global aerosols had dropped as much as 20 percent from the relatively stable level between 1986 and 1991.

The NASA study also sheds light on the puzzling observations by other scientists that the amount of sunlight reaching Earth’s surface, which had been steadily declining in recent decades, suddenly started to rebound around 1990. This switch from a “global dimming” trend to a “brightening” trend happened just as global aerosol levels started to decline, Mishchenko said. (source)
Put another way, about the time everyone started fretting about global climate change because of big, bad humans, the nice humans were cutting pollution, causing more sunlight to hit the earth, and temperatures to climb.

So is global warming really just a dearth of volcanic activity? Or is it the fact that we're doing such a good job of cutting our pollution? Or is it cataclysmic changes in global patterns that will kill us all and make Al Gore rich?

It's anyone's guess, so count on opportunistic politicians and panic-prone lefties to call for cuts in industrial production, higher taxes and big government programs to attack the problem!

Gee, perhaps if we just took off enough of the pollution control equipment to let the atmosphere really gunk up again, we'd enter a period of global dimming, and voila!, no more global warming!

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