The Guardian view on climate change: a global heatwave | Editorial

The weather in Britain is only a small part of a global pattern and as the Arctic warms, it will make extreme events into the new, and dangerous, normalThe British are parochial about weather. It is our cherished grievance, not to be shared with foreigners. Perhaps it is the fact that our weather tends to come from the west, across the Atlantic, and not from our neighbours in Europe (unless it's a "beast from the east") which reinforces the belief that our weather is a uniquely British problem. But though we cannot say definitively that the current heatwave is caused by carbon emissions, it fits the pattern of long-term changes that we call climate. It is part of a global phenomenon, even if not the most important part. The really significant change is happening in eastern Siberia at the moment, where a completely unprecedented heatwave is warming that Arctic coastline, with consequences that are unpredictable in detail but surely bad on a large scale.Siberia is a vulnerable point in the global climate system for two reasons. The obvious one is the Arctic ice. The more that melts, the less remains to reflect heat back into the atmosphere. Water, being dark, absorbs heat better so there is a feedback loop set up. That is worrying, but it may be less dangerous than the feedback caused by the melting of the layer formerly known as the permafrost. This releases carbon and methane - more methane will be released from under the warming sea - and both are powerful greenhouse gases. Instability in the Arctic affects the whole of the northern hemisphere, as it increases the chances that the northern jet stream, will stick for longer than usual in a particular pattern. When that happens, the weather stops changing in the affected areas. Heatwaves are prolonged and so are cold snaps. Extremes of every sort, such as the rains in Japan which have killed more than 100 people, become more likely. What seems to be happening at the moment is that a fixation of the jet stream has produced the heatwave in Siberia as well as ours here. Again, this is yet another feedback loop. This is a heatwave which makes further, hotter heatwaves more likely in the future. Continue reading...