European Winter and Global Warming
One comment received on my last editorial about global warming pointed to the recent cold weather in Europe. It suggested the deep snow and low temperatures showed global warming was not taking place.
Worth a response, so here goes.
Climate scientists have long been aware of the link between higher temperatures in the Arctic Ocean which have melted sea ice in the summer months and the increased risk of colder winters in Europe. A 30 year reduction in Arctic sea ice has begun to change wind patterns over much of the northern hemisphere. This in turn causes cold, Arctic air to be funneled over Britain during winter, replacing the mild Westerly airstream that normally dominates. In fact, the authoritative study on this appeared in 2009 – that is, before these two last cold winters. It actually predicted what we are now experiencing and predicted snowy weather in winter will be three times more frequent than in the past.
The warming of the air over now-ice-free seas and this causing colder winters, was predicted by the Potsdam Institute for Climate Impact Research. A lack of ice on the Barents and Kara Seas promotes the formation of a high pressure system there and that brings cold, polar air right into Europe.
According to Professor Stefan Rahmstorf from the institute, there has been a massive change. We used to have an ice-covered ocean, the ice acting like a lid on the water. Now the ocean is exposed ; the water is warmer than the atmosphere above it ; therefore, without ice trapping its heat, the ocean warms up the atmosphere. Hence the high pressure system forms above those seas and forces the colder air clockwise around the high, and right into Europe.
These scientists attach the normal qualifications about weather being complex and the possibility other factors are at play.
Interviewed in The Independent (December 24) Rahmstorf sketches a worrying prognosis however. He says that in the context of general warming the ice cover will be lost for longer each year and we will shift back to warmer winters caused by warmer air mass.
Rahmstorf says the last two cold winters are a transient phenomenon. “In the long run, global warming wins out.”
It remains mankind’s craziest experiment, as The Economist put it. And the climate change denial that has thwarted needed action is based on a quasi-religious faith that it can’t happen because it can’t happen.