Greenland meltwater threatens to shave 10‑20% off Atlantic currents, but a full shutdown appears unlikely

Greenland meltwater and the future of the Atlantic Meridional Overturning Circulation

Greenland meltwater pouring into the North Atlantic is poised to amplify the weakening of the AMOC by ↓ 10‑20% beyond the decline already projected for the century, a new study reports. Researchers integrated a dynamic ice‑sheet model into the EC‑Earth3 climate system and found that by 2100 the added freshwater will tip the balance, while by 2300 the cumulative effect could erode another ↓ 40% of the circulation’s strength.

The AMOC, the oceanic conveyor that shuttles heat northward and cold water southward, has been on a long‑term slide, now at its weakest in over a millennium, according to Reuters. A further slowdown threatens harsher winters in Northwestern Europe, accelerated sea‑level rise along the U.S. East Coast, and expanding drought belts near the equator.

Why Greenland matters more than previously thought

Most climate simulations already factor Arctic melt, but the Greenland contribution has been sidelined because its runoff was assumed less volatile on decadal scales. “Capturing Greenland’s melt requires a dedicated, high‑resolution ice‑sheet model,” explains Jost von Hardenberg, professor at the Polytechnic University of Turin. The team borrowed the Community Ice Sheet Model version 2 (CESM2) data and overlaid it onto EC‑Earth3, allowing a clean “with‑and‑without” experiment.

“The system does not flip into a dead state; it weakens strongly but remains operational,” von Hardenberg told Live Science.

When the simulated meltwater pulse was switched off, the AMOC rebounded partially; eliminating greenhouse‑gas emissions restored it fully. This resilience contrasts with earlier projections of an abrupt, irreversible shutdown.

Experts not involved in the work caution that a single‑model experiment cannot settle the debate. Jonathan Baker of the Met Office notes that replicating the test across a broader model ensemble is essential. Yet Nicholas Foukal of the University of Georgia finds the conclusion “robust,” pointing out that only massive freshwater inputs—far exceeding Greenland’s output—could drive a permanent collapse.

Future model generations will embed Greenland’s melt dynamics directly, narrowing the uncertainty envelope around AMOC forecasts. As von Hardenberg puts it, “A larger, more diverse set of simulations will let us answer how much the Atlantic conveyor will weaken under each emissions pathway.”

Editor’s note: A prior version misstated the 2300 projection as 2030; the correction has been applied.

Words by Elena Rostova (Socio-Economic Trends Analyst).