Two chaps from Columbia University have published a scheme for chemically extracting carbon dioxide from the atmosphere by passing it through a "chemical sponge". Critics of the scheme point out that the extraction process would be powered by electricity, and that we’d be better off cutting down the amount of greenhouse gas emissions we produce rather than looking for ways to recapture them. I’m no climate scientist, so I can’t pass judgement on which is the better plan … but at least there’s evidence that the prizes like Richard Branson’s Earth Challenge get people thinking about solutions to the big problems. [FuturePundit] [Image by Ju-X]