This is the confidence of one paper from one analysis technique. They might be right, or maybe not. Stefan Rahmstorf has a summary at realclimate.org and concludes:
Timing of the critical AMOC transition is still highly uncertain, but increasingly the evidence points to the risk being far greater than 10 % during this century – even rather worrying for the next few decades. The conservative IPCC estimate, based on climate models which are too stable and don’t get the full freshwater forcing, is in my view outdated now.
Deja vu all over again. We did this thread topic just two weeks ago. Where is our institutional memory?
From the CNN article on the paper:
“Scientists uninvolved with this study told CNN the exact tipping point for the critical system is uncertain, and that measurements of the currents have so far showed little trend or change. ”
And speaking of little trend, Fraser and Cunningham reconstructed the AMOC (Atlantic Meridional Overturning Circulation) back to 1900. Looking at their Figure 3, it can be seen that the current strength is now where it was in 1910 and stronger than it was in 1900 and 1970.
So, no resolution on the condition of the AMOC. Certainly not ‘settled science’. The current has large interdecadal variability.
Jackson et al. found that “the observed decrease in the overturning circulation is consistent with a recovery following a previous increase.” https://www.nature.com/articles/ngeo2715
DB2
In the distant past, the AMOC crossed the tipping point, causing large climate changes.
Predicting the exact location of tipping points, in climate and pretty much every field of science, is very hard and is the subject of intense research.
Human caused climate change is pushing us closer to the tipping point, but we don’t know how far away we still are.
Large, rapid changes in the AMOC are a serious risk but not a certainty.
In the words of the famous philosopher, Harry Callahan,
IIRC, that was due to the sudden emptying of an enormous glacial lake in Canada, Lake Agassiz, larger than the Black Sea. I don’t see anything like that at present.
According to Wikipedia, the Black Sea has 547,000 cubic km of water. The Greenland ice sheet has about 3,000,000 cubic km of ice. That’s about 8% of the global supply of fresh water.
