Some scientists came up with a crazy idea to combat global warming: deliberately spewing a layer of pollution into the atmosphere that reflects sunlight.
Tom Wigley, a senior U.S. government climatologist, followed Crutzen's article with a paper of his own on 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 shot so much sulfurous debris into the stratosphere that it is believed it cooled the Earth by .9 degrees 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.