A recently measured slowdown of 10 to 15 percent may be part of larger decline that began in the 1990s and shows no sign of stopping yet, scientists at the University of Reading reported Tuesday.
The Atlantic Meridional Overturning Circulation, which brings warm tropical waters linked to the Gulf Stream up to the latitudes of Britain , is an important contributor to Europe's warm and temperate climate, they said.
This weakening of the AMOC is likely to cause a cooling of the North Atlantic Ocean, which has until recently been in a "warm" phase, and could cause a reversal of the recent pattern of wet summers in Britain, cause fewer Atlantic hurricanes, and potentially bring damaging droughts in the Sahel region of North Africa, the researchers said.
"There's lots of evidence that the AMOC is important for European climate, and seeing how these events unfold is a great opportunity to understand this influence better," Reading researcher John Robson said.
"In Britain we could see a return to drier summers, although it could also lead to more droughts in parts of Europe and Africa. However, there's quite a bit of uncertainty about how fast changes might happen, and other influences -- such as sea ice and greenhouse gases -- are also important."