And the problem is serious, climate scientists say. If current trends continue, the Earth's average surface temperature will be 2.7 to 11 degrees Fahrenheit higher in 100 years, they project.
One solution envisions blasting tiny particles into the atmosphere from the guns of battleships. The particles would deflect enough sunlight to trigger global cooling. Another falls under the category of "geo-engineering": launching 50,000 mirrors into orbit to reflect sunlight back into space.
"The sooner, the better," says Dr. Edward Teller, a promoter of the plan. Teller, who helped harness the destructive power of the atom 60 years ago, now believes man can dim the power of the sun.
"The simplest is to put into the high atmosphere small particles that scatter away one or two percent of the sunlight,"he says.
Teller's colleague at Lawrence Livermore Laboratory, climate researcher Ken Caldeira, had hoped to prove Teller wrong.
"My first thoughts about this was that it simply wouldn't work," he says.
Then he ran the computer models, Caldeira says.
"Much to our surprise, our model results indicated that geo-engineering schemes would move our climate back to what it was before," he says.
Back to cooler temperatures, that is. And Caldeira says the best way to go about it is by "putting a huge satellite out in space between earth and sun."
That could mean putting the device where the SOHO satellite is now observing the sun's solar storms. The huge solar shield would act as an orbiting sunshade to cool the earth.
"The satellite in space would leave a little pockmark on the surface of the sun, roughly two percent of the sun's surface area," Caldeira says.
And the Caldeira scheme wouldn't have the downside of blasting particles into space, a technique that would turn blue skies absolutely white. Or that of the 50,000 orbiting mirrors, which would create a flickering sun here on earth.
But some global warming experts, like Stanford University's Steve Schneider, have their doubts about geo-engineering.
"We don't know what the precise effects would be, whether the cure would be better or worse than the disease," Schneider says.
Eliminating harmful greenhouse gases will take 200 yearsfar longer than global cooperation can be expected to last, Schneider says.
"Two hundred years of continuous planetary management on a global scalethat's asking a lot of political institutions that have never been able to get along for more than a few decades at a time," he says.
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