Wednesday, July 4, 2012

As the climate changes, extreme weather isn't that extreme any more

John Vidal in the Guardian (UK): Britain and northern Europe are dripping their way into what is already being called a "lost summer". We have had our wettest April and June and our coldest spring, and there is no end in sight of the abnormal weather. But we can take some comfort in the fact that we are not alone.

In the US, 100 million people in 17 states have now had to be warned about the dangers of one of most intense heatwaves of the last century. Life in many US cities has become unbearable, with temperatures well over 100F (38C) lasting for many days now. More than 40,000 temperature records have already been set in the US this year and freak storms, record rainfall and giant forest fires have left millions suffering. Many old people will certainly die in the heatwave and food prices are bound to rise.

But this extreme weather is far more widespread than just northern Europe or the US. May was the second warmest ever recorded worldwide and the warmest on record for the northern hemisphere. The link between a warming atmosphere and individual climatic events is unclear but no one should doubt the physical turmoil. In the last few weeks we have seen the Arctic sea ice melting at a record pace, the Amazon reaching its highest level on record, massive forest fires in Siberia and the Russian east, temperatures climbing to a barely imaginable 48C in northern India, and an abnormally strong monsoon which has so far left many hundreds dead and nearly 7 million people homeless from floods in Assam and southern Bangladesh.

There's always been freak weather, but climatologists increasingly think these events are becoming less unusual. Instead of taking place every 10 or 20 years, they are happening every two or three. This, they are beginning to say, is the new normal, a taste of the future as the planet warms....

Thunderstorms over Brazil, seen from the Space Shuttle Challenger in 1984.

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