UK Weather 2012–Cold And Wet!
By Paul Homewood
2012 was the second coldest year since 1996, second only to 2010, when a bitter winter brought temperature crashing down. Despite the first three months of the year being actually very mild, the annual temperature was only 8.76C, below the 1981-2010 average of 8.85C.
The average for 2008-12 is close to the long term average, running at 8.92C, and is considerable down on the 2003-07 figure of 9.55C, suggesting that the increase in temperatures from the mid 1990’s has well and truly run its course.
Since 1910, there have been 34 years that were warmer than this year.
“The AMO has affected air temperatures and rainfall over much of the Northern Hemisphere, in particular, North America and Europe.”
The previous warm phase of the AMO was between 1930 and 1960. During this time, the average UK temperature was 8.52C, i.e only about 0.4C lower than current trends indicate.
Such a small amount over 50 years does not seem to be much of a cause for alarm!
Brits won’t need reminding that 2012 was one of the wettest on record.
Unsurprisingly, the Met Office’s Julia Slingo blames it on global warming.
“The trend towards more extreme rainfall events is one we are seeing around the world, in countries such as India and China, and now potentially here in the UK. The long-term trend towards wetter weather is likely to continue as global air temperatures rise. “
It is good, therefore, to see a bit of honesty from the BBC’s weatherman, Steve Cleaton, who tells us:-
“This drastic change was largely attributed to a shift in the position of the jet stream, a fast moving ribbon of air that flows high in the atmosphere. The jet stream helps create and steer low pressure systems towards and across the UK, and tends to meander from north to south through the year.
The extent of the jet stream’s meandering largely results from the natural variability of our weather. During 2012, the jet stream was positioned to the south of the UK for extended periods of time.
This set-up resulted in the prevalence of Atlantic weather systems to be drawn across the UK from the west, bringing all the wet weather. “
The effect of the change in jet stream is very vividly illustrated in the Met’s rainfall map, below.
Much of Scotland, that normally gets most of the rain, has been drier than normal. Instead the rain bearing belts have, this year, shifted southwards. Depressions, that would normally have caught the fringe of Scotland and headed off into the North Sea, have instead been dumping rain further south. As a knock on effect, the back edge of many such low pressure systems have swung back across the North of England.
There is much more detail I wish to go into on this year’s rainfall, so I will be devoting a separate post to the subject in the next few days. But I will leave a couple of thoughts, that the useless Slingo might like to cogitate on.
1) In 2011, Slingo produced a paper for the Met, entitled “Climate: Observations,projections and impacts”. She then wrote that, under a warming climate:-
Europe shows a strong contrast in projected precipitation changes, with large decreases in the south and large increases in the north. The UK falls towards the northern region with generally increasing precipitation, with projected increases of up to 10%, though some southern parts of the UK may experience decreases of up to 5%.
2) Last year, DEFRA produced their “Climate Change Risk Assessment”, which predicted:-
An increase in winter rainfall of upto 70%, and a decrease in summer rainfall of upto 60%.
The experience in the last few years, including 2012 has been the opposite.
Perhaps Slingo let the cat out of the bag when she said “Much more research is needed to understand more about the causes and potential implications."
Will another million do, Julia?