8 January 2010

heavy snow in the UK means global warming is over, right?

A number of people have tried to suggest that this week's snowy weather is proof that global warming is a myth. The Conservative MP Ann Winterton was rightly jeered when she said this in the House of Commons. She's quite wrong, as are those at the other end of the belief spectrum who claim the cold snap is evidence that the Gulf Stream has suddenly stopped.

Here's what the Met Office has to say about the current snowfalls: "In most winters, and certainly those in the last 20 years or so, our winds normally come from the south-west. This means air travels over the relatively warm Atlantic and we get mild conditions in the UK. However, over the past three weeks the Atlantic air has been ‘blocked’ and cold air has been flowing down from the Arctic or the cold winter landmass of Europe.

"The cold temperatures in the UK have also been accompanied by snow. This is because areas of low pressure have been running in from the north-east, tracking across the North Sea and picking up moisture along the way. When they come over the land, the water falls as snow due to the cold temperatures."

Writing in The Times, weather expert Paul Simons alleged that there was a big change afoot: "There are signs of a sudden shift in the temperature of the stratosphere, several miles high in the atmosphere. For reasons not entirely clear, the temperature of the stratosphere has increased and this has impacted down into the lower atmosphere, where most of our weather occurs."

Interesting but it sounds like a theory in need of a bit more research.

Dr Myles Allen, head of the Climate Dynamics group in the Department of Physics at Oxford University, was quoted in The Daily Telegraph as saying: "Snowfall ... could actually increase in the short term because of global warming. We have all heard the expression 'too cold to snow' and we have always expected precipitation to increase. All the indicators still suggest that we are warming up in line with predictions."

That makes sense. Climate change models predict wetter winters. And that almost certainly means snowier winters for the foreseeable future. So we'd better get used to it.