Maps below show the temperature anomaly for the past three months and the seasonal mean (Northern Hemisphere Summer). We draw attention to the cool region southeast of Greenland and warmth in the middle of the North Atlantic.
Wally Broecker suggested decades ago that freshwater injection onto the North Atlantic could cause shutdown of the overturning ocean circulation (AMOC, Atlantic Meridional Overturning Circulation). Rahmstorf et al. (2015) present evidence that a 20th century trend toward the cooling southeast of Greenland was due to a slowdown of AMOC, linking the trend to observed freshening of the North Atlantic surface water that may have been due to some combination of anomalous sea ice export from the Arctic, Greenland melt, and increased precipitation and river runoff.