There are about 20 major climate simulation models focused on ocean calculations at different research labs around the world. All of those models show the AMOC

There are about 20 major climate simulation models focused on ocean calculations at different research labs around the world. All of those models show the AMOC to be meta-stable (meaning it rapidly flips from on to off, as opposed to long gradual slowing). All of those models show the AMOC is on track to shut off "soon." All of those models show an AMOC shutoff event to be very serious, particularly for Northern Europe, but also for the world as a whole. Prior to this paper, the estimates on what "soon" meant were not very good and generally took the form of "it could be this century, or it could be in the next couple centuries." This paper has not been through peer review yet, but the authors are significant participants in the field. The paper is trying to answer one of the most important question in science right now, which is how long until the AMOC shuts down and what signals should one watch for to improve that prediction.