Summers to become drier in Britain?

Researchers believe that the weather in Britain could become drier during summers due to a change in the North Atlantic current.

Experts say the slowing of the current, which has been up to 15 per cent slower in the past 10 years and is linked to the Gulf Stream, could cool the North Atlantic and bring dry summers to the UK in the future.

Dr Jon Robson, of the National Centre for Atmospheric Science (NCAS) at the University of Reading, told The Daily Telegraph: "Our findings suggest there could be a relative cooling of the North Atlantic sooner rather than later, perhaps over the next decade or so.

"In Britain we could see a return to drier summers, although it could also lead to more droughts in parts of Europe and Africa."

But Leon Brown, chief forecaster at The Weather Channel, tells AOL Travel: "With a short history of observations in the North Atlantic it is difficult to predict what will happen, or if there are cycles in the North Atlantic Drift current.

"Basically the Gulf Stream is a very warm and strong surface current which flows up past the east coast of the US and then spreads out across the Northern Atlantic in large eddies as it mixes with the Labrador current off New Foundland, and is called the North Atlantic Drift.

"This surface current keeps sea temperatures at 50 to 70N in the Northeast Atlantic, between Iceland and Scandinavia - a lot warmer than they would be otherwise.

"The Gulf Stream current is actually quite shallow at the surface and there are theories that with extra melt water from Greenland, the less dense and fresher water from the melting ice, such as the Labrador Current, could override the denser, warmer and saline current, pushing it beneath the surface."

Leon says that this could in effect lower the North Atlantic temperatures quite sharply around the shores of the UK and Scandinavia. There are theories that this could happen suddenly or is a more gradual process, but measurements currently suggest the current is continuing to becoming weaker in the Northeast Atlantic.

"If sea temperatures are lower, less moisture is evaporated to the atmosphere and hence rainfall over Northwest Europe in the prevailing westerly winds would be lower in the summer and winter," Mr Brown adds.

"Summers would trend drier and probably hotter and sunnier, while winters would be longer, colder and drier with a shorter spring. The jet stream would also take a more southerly track if the North Atlantic cooled and hence change weather patterns over a much larger area than just Northwest Europe with impacts on the distribution of precipitation around the northern hemisphere.

"However, why the Artic Sea ice has declined so rapidly recently, and the impacts on the weather patterns, aren't understood either. Changes to the Atlantic currents are just one small part in the ever changing global ocean and atmospheric cycles that interact to give us our daily and seasonal weather in Britain, and predicting the future remains as challenging as ever."

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