Britain may be in the grip of the coldest winter for 30 years and grappling with up to a foot of snow in some places but the extreme weather is entirely consistent with global warming, claim scientists.
Temperatures for December and January were consistently 1.8 F ( 1 C) lower than the average of 41 F (5 C)and 37 F (3C) respectively and
more snow fell in London this week than since the 1960s.
But despite this extreme weather, scientists say that the current cold snap does not mean that climate change is going into reverse. In fact, the surprise with which we have greeted the extreme conditions only reinforces how our climate has changed over the years.
A study by the Met Office which went back 350 years shows that such extreme weather now only occurs every 20 years.
Back in the pre-industrial days of Charles Dickens, it was a much more regular occurrence - hitting the country on average every five years or so.
During that time global temperatures has risen by 1.7 F (0.8 C), studies have shown.
"Even though this is quite a cold winter by recent standards it is still perfectly consistent with predictions for global warming," said Dr Myles Allen, head of the Climate Dynamics group at Department of Physics, University of Oxford.
"If it wasn't for global warming this cold snap would happen much more regularly. What is interesting is that we are now surprised by this kind of weather. I doubt we would have been in the 1950s because it was much more common.
"As for snowfall that 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."
This winter seems so bad precisely because it is now so unusual. In contrast the deep freezes of 1946-47 and 1962-63 were much colder - 5.3 F (2.97C) and 7.9 F (4.37C) cooler than the long-term norm.
And with global warming we can expect another 1962-63 winter only once every 1,100 years, compared with every 183 years before 1850.
Dave Britton, a meteorologist and climate scientist at the Met Office, said: "Even with global warming you cannot rule out we will have a cold winter every so often. It sometimes rains in the Sahara but it is still a desert."
Scientists point out that the people must distinguish between climate and weather. Weather is what happens in the short term whereas climate is the long term trend.
"Just as the wet summer of 2007 or recent heat waves cannot be attributed to global warming nor can this cold snap," said Bob Ward, spokesman for the Grantham Research Institute for Climate Change at London School of Economics.
"What is important to do is look at the long term global trends and they are still up. What we experience in the short term in this country is not important. After all, Melbourne had a heat wave last week."
As for the suggestion that the recent cold weather is due to a reversal of the warming Gulf Stream and the North Atlantic Drift - otherwise known as the Thermohaline Circulation - this has been mostly ruled out by recent research.
"It has a very low chance of happening and if it does occur it will be in centuries time," added Mr Ward.
The North Atlantic Drift is an extension of the Gulf Stream which brings warm tropical water from the Gulf of Mexico to northern Europe, including Britain. Its effect is to bring up the average temperature.
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