Sea surface temperatures in the subpolar North Atlantic have been cooling since 1900, despite global warming. This cooling, known as the North Atlantic cold blob, is partly caused by a more positive North Atlantic Oscillation (NAO) pattern. The positive NAO increases surface winds, leading to more heat loss from the ocean. The NAO-induced heat loss alone can explain 67% of the observed cooling trend. This suggests that besides ocean currents, changes in atmospheric circulation have also played a significant role in cooling the subpolar North Atlantic over the past century.