Collapse related because it shows a regime shift in 2015 regarding sea ice extent around Antarctica. Large decreases in both Maximums and Minimums combined with a sharp increase in Radiative Forcing Anomaly around the same time.

"A regime shift has reduced Antarctic sea-ice extent far below its natural variability of past centuries, and in some respects is more abrupt, non-linear and potentially irreversible than Arctic sea-ice loss. A marked slowdown in Antarctic Overturning Circulation is expected to intensify this century and may be faster than theanticipated Atlantic Meridional Overturning Circulation slowdown."

Link to Paul Beckwith discussing this paper in the comments

I also want to hijack this to ask why no one talks about the Antarctic Bottom Water (AABW). The AABW is 30-40% of the global ocean volume and 58% of the global ocean floor compared to just 26% for North Atlantic Deep Water (NADW). As salt water freezes, it expels salt which forms a hypersaline, dense, cold current. The current carries oxygen to the deepest parts of the ocean, helping to support life at the sea floor.

If this current collapses, as some scientists predict it could by 2050, the impacts would be more than catastrophic. Ignoring the sheer amount of heat and carbon sequestered by the current (As by then, further increases in warming would be moot imo, explain why in a second), the lack of oxygen in the deep ocean will crash that ecosystem. Why is that bad? The deep water ecosystem provides the bulk of the nutrient rich water that phytoplankton rely on. Phytoplankton being the driver of 50-85% of our oxygen... well, that is why I said further warming would be moot...

Everyone always focuses on what are we going to eat as temps rise, where are people going to get water...

I think about, what will we breathe?