HERE鈥橲 the question to put to all those who that the recent severe winter conditions prove that global warming is nonsense: 鈥淣ext time there鈥檚 a heatwave in summer or an unusually mild spell in winter, will you publicly accept that the 鈥榳armists鈥� were right all along? If not, why not? If a cold snap means the climate is getting colder, surely a spell of hot weather proves it is getting warmer?鈥�
The point, of course, is that a bout of extreme weather does not prove anything about climate change. Climate is the average weather over decades.
That said, it is perfectly reasonable to ask why, if the world is warming, have so many places in the northern hemisphere been experiencing record lows? The answer is that for the past few decades cold Arctic air has mostly stayed in the Arctic over winter, trapped by strong winds spinning around the pole. This winter the vortex has weakened and in many places cold air is spilling further south than usual.
Advertisement
The result has been freezing weather for places as far afield as Florida, China and the UK. However, the Arctic, Greenland, much of the Mediterranean and southern Asia have been warmer than usual. So overall the northern hemisphere winter may be no colder than in previous years, it鈥檚 just that the heat is . Indeed, the average surface temperature of the entire planet during January may yet turn out to be .
鈥淭he surface temperature of the planet in January may turn out to be one of the warmest on record鈥�
Most atmospheric scientists regard the recent weather as nothing more than the kind of extreme event that happens from time to time. Others are not so sure. Xiangdong Zhang of the International Arctic Research Center in Fairbanks, Alaska, has found that atmospheric circulation patterns in the Arctic are as it warms. He says these changes might have contributed to the recent unusual weather.
Either way, some areas could have more cold weather in the future. That will not change the big picture: the world warmed over the 20th century and it is going to get warmer still. Anyone who tells you a cold spell proves otherwise is either intellectually challenged or plain dishonest.
Update 10 February: that according to satellite measurements, this January was the warmest since records began in 1979.
