Gulf Stream Cooling
Peter Wadhams, Professor of Ocean Physics at Cambridge University, used ships and Royal Navy submarines to take measurements across the Greenland Sea. He found that the sinking of supercooled water in the Sea has weakened to less than a quarter of its former strength.
With that mechanism slowing, the circulation of warm water around the globe will slow. Britain, which lies on the same latitude as Siberia and ought to be much colder than it is, gets warmed by the Gulf Stream by 5-8C. One possibility is that Europe will freeze; another is that the slowing of the Gulf Stream may keep Europe cool as global warming heats the rest of the world ? but with more extremes of weather.