Washington (AP) -- Planet getting too hot? Pull down the shade, the big one.
Global warming is inspiring engineers to devise responses that one NASA scientist says range from "great" to "idiotic." The space agency is putting the finishing touches on a report summing up some of them.
One of them is the "Sun Shade" concept. University of Arizona astronomer Roger Angel says sending an enormous fleet of small spaceships into orbit to form a kind of umbrella could lower the sun's heat by about two percent.
Other scientists note that volcanoes have shaded and cooled the earth by sending sulfate particles into the atmosphere. They suggest using cannons, balloons or jet engines to do the same.
Then there's the Geritol solution, already being carried out by a private California company. It's dumping tons of iron dust into the ocean, hoping to create giant algae blooms that will soak up carbon dioxide. Marine scientists warn this approach could dramatically affect marine life.
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