20130325_IT

Source: ITV News

URL: http://www.itv.com/news/2013-03-25/extreme-weather-will-become-more-likely-in-uk-as-climate-changes/

Date: 25/03/2013

Event: Sir John Beddington: "these extreme events are more likely because climate change has happened"

Attribution: ITV News

People:

• Sir John Beddington: UK Government Chief Scientist
• Lawrence McGinty: ITV News Science Editor
• Ewen McCallum: UK Met Office Chief Meteorologist

Lawrence McGinty: Believe it or not, summer starts officially on Sunday. Tell that to people on the Isle of Arran, who say these are the worst conditions they've ever seen. Met Office yellow warnings for snow and ice are falling as thick as the snowdrifts. I asked the government's Chief Scientist whether extreme weather events, like this cold spell, are linked to climate change.

Sir John Beddington: What you can say is these extreme events are more likely because climate change has happened. There's always natural variability in weather, and you can point to history to show that there's been natural variation. But what we've been able to analyse shows that the probability, the chances of these more extreme events has been increased by the fact of having climate change.

Lawrence McGinty: The current extreme weather is all to do with what's happening high above the clouds in what scientists call the jet stream. The jet stream is a ribbon of air, five to seven miles high, moving at up to 200 miles an hour. It's driven by differences in temperature between cold Arctic air and warmer air further south. One theory is that with Arctic warming, this driving force is reduced, slowing down the jet stream, which meanders in large curves, like a slow-flowing river. When Britain is in a trough in these waves, cold air moves in from the north. This is the jet stream now. [Brightly-coloured graphics are on screen.] It shows up as red areas in this satellite picture. Britain is sitting above the jet stream, which means cold air moving in from the north.

Ewen McCallum: We're getting towards the end of March now, and you'd expect temperatures to be picking up as the Sun gets much higher in the sky. But in fact this is very, unusually cold. It looks as though it could be the coldest March in about 40 years.

Lawrence McGinty: The Met Office today extended its cold weather warning until Friday, and the bookies are offering odds-on that this Easter will be a white one. Lawrence McGinty, ITV News.