(CNN) -- The idea of intervening and modifying the earth's climate is not a new one. The U.S. National Academy of Sciences believes that of erecting a vast bank of mirrors in space to reflect and block out sunlight would lower temperatures. And Nobel Prize winning Dutch chemist Paul Crutzen thinks that blasting rockets laden with sulfur into the stratosphere would create a protective and cooling 'blanket' for the earth. But there are some more down to earth projects currently in operation. Capturing carbon in 'synthetic trees' is just one of these.
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