LONDON (Reuters) - Severe winter freezes, like the one gripping parts of Europe over the last few weeks, will become increasingly rare because of the warming effect of climate change, the UK's official forecaster said on Tuesday.
Europe's deep winter freeze, partly due to the El Nino weather phenomenon, has shocked parts of northwest Europe that usually escape the coldest winter temperatures, driving heating gas demand to records in Britain and disrupting supplies of the fuel when it was most needed.
The winter so far has been one of the coldest for nearly 30 years in Britain, but such icy weather was more common in centuries past and should become even rarer going forward.
"Winters like this are likely to become less of a feature as we head through the 21st century," John Hammond, a meteorologist at the UK Met Office said on Tuesday.
"Colder winters become less likely because overall the background warming will reduce the severity of them, certainly for our part of the world."
The Met Office expects Britain's already relatively mild and damp, on average, winters to become increasingly warm and wet as a result of climate change, with the effect particularly pronounced in the latter part of the century.
While this year's winter freeze seems particularly severe, in the "Little Ice Age" that preceded Britain's Industrial Revolution, the climate was cold enough in London for the River Thames to freeze over, allowing "Frost Fairs" to be held on it.
Most climate scientists now say the increase in carbon dioxide emissions, that began with the industrialization of Europe in the 18th century, has had a warming effect on the worlds climate.
Global temperatures may be 4 degrees Celsius hotter by the mid-2050s if current greenhouse gas emissions trends continue, according to some long term forecasts.
The World Meteorological Organization said last month that 2000-2009 was the hottest decade since records began in 1850, and that 2009 would likely be the fifth warmest year on record. WMO data show that eight out of the 10 hottest years on record have all been since 2000.
In the short term, the Met Office expects night-time temperatures just below freezing in many parts of Britain for the rest of the week, but expects temperatures to remain well above last week when parts of the country dipped below minus 20 degrees Celsius.
"It stays cold much of this week, but we are starting to see something of a transition to less cold air, something of an Atlantic influence for a time," Hammond said.
"It's a reluctant increase in temperatures as we go through the rest of this week and through the weekend in particular."
Britain usually escapes the winter freezes of continental Europe because of relatively mild weather brought by south westerly winds from the Atlantic.
The icy weather of the last two weeks has been brought by Arctic winds mixed with cold and dry easterly winds from Russia.
A low pressure system promises to spread across Britain from the Atlantic this weekend, pinning back the high pressure systems sitting over northwest Europe on Tuesday.
But colder air over Scandinavia and north east Europe could creep west again next week.
"It's very much a battle ground at the moment for the weather patterns," Hammond said.
Reporting by Daniel Fineren; Editing by Keiron Henderson