AMOC weakening trajectory now consistent with committed collapse under current emissions and Greenland melt rates

Recent observational syntheses combine Florida Straits transport records, subpolar sea-surface temperature fingerprints, and sediment-derived sortable silt data. These converge on a multi-decadal decline that accelerated after 1995, coinciding with increased Greenland freshwater discharge of approximately 0.1 Sverdrup. The New Scientist framing correctly identifies the dependence on future emissions yet understates how close present cumulative forcing already sits to modeled bifurcation points derived from CMIP6 hosing experiments.

Paleoclimate analogs from the Younger Dryas and Heinrich events demonstrate that once freshwater input crosses a critical range, recovery can require centuries even if forcing is later removed. Current Greenland mass-loss rates, now exceeding 280 Gt per year, already overlap the lower end of hosing thresholds that trigger collapse in intermediate-complexity models. This suggests the relevant policy window may be narrower than the 2050–2100 horizon typically cited.

Economic and weather consequences would propagate through altered European storm tracks, Sahel rainfall, and North Atlantic hurricane activity. No large-scale observational array currently resolves the full three-dimensional circulation at the resolution needed to detect an approaching critical transition with high statistical power.

Strengthening evidence requires sustained funding for the RAPID and OSNAP mooring arrays plus assimilation of new SWOT altimetry into eddy-permitting models to reduce uncertainty in freshwater transport estimates.