New Model Sees AMOC Weakening 80% by 2300, Not Irreversible Collapse
Updated
Updated · New Scientist · Jul 1
New Model Sees AMOC Weakening 80% by 2300, Not Irreversible Collapse
1 articles · Updated · New Scientist · Jul 1
Summary
A new Utrecht University climate model found Greenland meltwater would weaken the Atlantic Meridional Overturning Circulation gradually rather than trigger a sudden, irreversible shutdown.
The simulations showed atmospheric warming alone cuts AMOC strength by 60% by 2300, while rising Greenland meltwater adds another 20% decline by freshening North Atlantic waters and slowing deep-water sinking.
If atmospheric CO2 then falls 1% a year from 2250, the model projects the circulation would fully recover by about 2400, suggesting no point of no return from Greenland meltwater alone.
An 80% AMOC drop could still freeze crops in western Europe, ice over the North Sea and disrupt tropical monsoons, even if the decline is gradual and potentially reversible.
Researchers and outside experts said the result does not settle tipping-point risk, noting other models still produce collapse under 21st-century warming and that Antarctic melt could also alter the system.
Recent climate models show that the Atlantic Meridional Overturning Circulation (AMOC) is expected to weaken significantly throughout the 21st century, mainly due to rising atmospheric carbon dioxide. This trend has already started, with the AMOC slowing since the mid-20th century. The risk of a drastic slowdown or even a complete shutdown after 2100 is higher than many realize, especially as increasing runoff from the Greenland ice sheet adds more freshwater to the ocean. Many models have not fully included this meltwater, which means the threat could be even greater than current projections suggest.