Speigel: Researchers have found alarming evidence that the frozen Arctic floor has started to thaw and release long-stored methane gas. The results could be a catastrophic warming of the earth, since methane is a far more potent greenhouse gas than carbon dioxide. But can the methane also be used as fuel? It’s always been a disturbing what-if scenario for climate researchers: Gas hydrates stored in the Arctic ocean floor — hard clumps of ice and methane, conserved by freezing temperatures and …