Guardian: Scientists claim to have discovered evidence for large releases of methane into the atmosphere from frozen seabed stores off the northern coast of Siberia. A large injection of the gas – which is 21 times more potent as an atmospheric heat trap than carbon dioxide – has long been cited by climate scientists as the potential trigger for runaway global warming. The warming caused by the gas could destabilise permafrost further, they fear, leading to yet more methane release. But …