there is real bad news on the global warming front. Stealthily-rising temperature has taken its toll, now, on Siberia's wetlands. They lay frozen for millennia, until now. Receding glaciers or ice-cover are already legion; these no longer qualify as good copy. But what's happening in Siberia has serious ecological consequences. For, buried beneath the permanently frozen subsoil of the western Siberian lowland are billions of tonnes of methane, a potent greenhouse gas. Scientists, for long, have considered the vast frozen peat bogs (wet spongy ground of decomposing vegetation) in Siberia a good carbon sink. It is estimated that about 70 billion tonnes of methane gas