Use smoke, mirrors to combat global warming?

When Mount Pinatubo erupted 16 years ago in the Philippines it cooled the Earth for about a year because the sulfate particles in the upper atmosphere reflected some sunlight.

Several leading scientists, from Nobel Laureate Paul Crutzen to the late nuclear cold warrior Edward Teller, have proposed doing the same artificially to offset global warming.

Using jet engines, cannons or balloons to get sulfates in the air, humans could reduce the solar heat, and only increase current sulfur pollution by a small percentage, said Tom Wigley of the National Center for Atmospheric Research.

“It’s an issue of the lesser of two evils,” he said.

Scientists at the Center for Atmospheric Research put the idea into a computer climate model. The results aren’t particularly cheap or promising, said NCAR scientist Caspar Ammann. It would take tens of thousands of tons of sulfate to be injected into the air each month, he said.

“From a practical point of view, it’s completely ridiculous,” Amman said. “Instead of investing so much into this, it would be much easier to cut down on the initial problem.”

Bullit Marquez / AP Mt. Pinatubo spews ash as high as 10 miles up in this June 19, 1991, photo. When Pinatubo erupted it cooled the Earth for about a year because the sulfate particles in the upper atmosphere reflected some sunlight.

Both this technique and the solar umbrella while reducing heating, wouldn’t reduce carbon dioxide. So they wouldn’t counter a dramatic increase in the acidity of the world’s oceans, which happens with global warming, scientists said. It harms sea life, especially coral reefs.

Despite that, Calgary’s David Keith is working on tweaking the concept. He wants to find a more efficient chemical to inject into the atmosphere in case of emergency.

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