Atlantic current change could bring drier summers
A change in the North Atlantic current could lead to the end of soggy summers, researchers have claimed.
Recent studies of the Atlantic Meridional Overturning Circulation (AMOC), a major warm current in the North Atlantic Ocean, have shown that it slowed down by up to 15pc in the past decade.
Now experts suggest that the slowing of the current, which is linked to the Gulf Stream, could be part of a larger decline which began in the 1990s and looks set to continue.
The AMOC contributes to the temperate climate of European countries by sweeping warm tropical waters northwards towards our latitudes, and stronger circulations have previously been linked to the increased likelihood of wet summers in Ireland and Britain.
A decline in its speed, however, could cool the North Atlantic and put an end to the pattern, bringing colder but drier summer weather to us in future, experts explained.
It could also have knock-on effects in other parts of the world, for example by lowering the risk of hurricanes in North America and raising the likelihood of droughts in North Africa, it was claimed.
Researchers from the University of Reading analysed direct measurements of the AMOC taken since 2004 and compared them against other recordings of changes in the deep North Atlantic.
When combined with computer simulations, the results, published in the in the Nature Geoscience journal, suggested that the slowdown in the AMOC may have begun several years earlier than previously thought, and may not be only a temporary phenomenon.
The findings will be familiar to fans of the sci-fi thriller “The Day After Tomorrow”, in which the AMOC suddenly shuts down, plunging the northern hemisphere into an ice age.
In reality the changes will be far less dramatic and will take place over decades rather than days, experts said.
Dr Jon Robson, of the National Centre for Atmospheric Science (NCAS) at the University of Reading, who led the study, said: “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,” he added. “There’s no evidence this slowdown has been caused by global warming, although we can’t rule out some link.”
Prof Rowan Sutton, research director of NCAS and a co-author of the research. added: “Those of us that spend our summer holidays in Britain would welcome a move away from a recent succession of soggy summers.
“But this research certainly isn’t a forecast for summer 2014, or any other year. However, it could suggest a trend towards drier summers in the UK. These changes in UK climate would occur on top of a longer-term man-made global warming trend.”