The surface of the world's ocean, particularly in the North Atlantic, has been warming for decades. There have been concerns that the thermohaline circulation and fundamental climate variables such as seawater temperature and salinity could undergo substantial changes in response to this surface warming. The Atlantic Meridional Overturning Circulation (AMOC) has changed significantly over the past century and may have slowed in recent decades. Concerns about the future of the climate in the North Atlantic are therefore justified. A key to understanding the current climate trajectory in the North Atlantic is to identify how the decadal climate responds to ongoing surface warming. This problem is addressed using data in situ from the World Ocean Atlas covering the years 1955–1964 to 2005–2017 and from the SODA reanalysis project for the last decades 1980–2019 as fingerprints of the three-dimensional circulation in the North Atlantic and AMOC dynamics. (Alexei Mishonov, Dan Seidov, more at frontiersin.org)