One of the more interesting (read 'unusual') suggestions made at the Nairobi talks was the possibility, in the bid to reduce the harmful build-up of heat in the atmosphere, of drawing a "shade" over the sun. In other words, if it's getting too hot - pull the curtains!

How? Simple - by building a layer of pollutants between us and the sun. Good idea? I'll let you be the judge...

The Nobel Prize-winning scientist, Paul J. Crutzen, that first put the idea forward, is of course not keen on the idea:

"It was meant to startle the policymakers," said Paul J. Crutzen, of Germany's Max Planck Institute for Chemistry. "If they don't take action much more strongly than they have in the past, then in the end we have to do experiments like this."

When he published his proposal in the journal Climatic Change in August, Crutzen cited a "grossly disappointing international political response" to warming.

Effects of Acid Rain in Germany CREDIT: © WWF-Canon / Mauri Rautkari

These are not just idle words. Mr. Crutzen and others have actually researched the possibility, and potential methods, for distributing reflective pollutants into the upper-atmosphere.

Tom Wigley, a senior U.S. government climatologist, followed Crutzen's article with a paper of his own Oct. 20 in the leading U.S. journal Science. Like Crutzen, Wigley cited the precedent of the huge volcanic eruption of Mount Pinatubo in the Philippines in 1991.

Pinatubo poured so much sulfurous debris into the stratosphere that it is believed it cooled the Earth by 0.5 degrees Celsius (0.9 degrees Fahrenheit) for about a year.

Wigley ran scenarios of stratospheric sulfate injection -- on the scale of Pinatubo's estimated 10 million tons of sulfur -- through supercomputer models of the climate, and reported that Crutzen's idea would, indeed, seem to work. Even half that amount per year would help, he wrote.

A massive dissemination of pollutants would be needed every year or two, as the sulfates precipitate from the atmosphere in acid rain.

The scariest part about this story is that delegates at the Nairobi conference were surprisingly open to the idea. Although, if we're considering polluting our own planet to reduce global warming, there are other 'out there' options to consider as well.