There is a radical proposal to close (or dam) the Bering Strait—the narrow sea passage between Russia (Siberia) and the US (Alaska)—has recently been modeled as a potential way to help stabilize or strengthen the Atlantic Meridional Overturning Circulation (AMOC), which includes the Gulf Stream system often loosely called the “Atlantic current.”

This is the core finding from the 2026 Science Advances paper by Jelle Soons and Henk Dijkstra (Utrecht University), titled exactly “The effects of a constructed closure of the Bering Strait on AMOC tipping behavior.”

The Bering Strait Throughflow (BST) currently moves ~0.8–1 Sv of relatively fresh Pacific water northward into the Arctic, which eventually reaches the North Atlantic via the Fram Strait and other pathways. This freshwater input reduces surface density in the sinking regions (Nordic Seas, Labrador Sea), counteracting the salinity that enables deep convection and sustaining the AMOC’s “on” state.

Closure effect on the “on” state (strong AMOC):

Blocking the strait reduces freshwater import to the Arctic/Atlantic system. This keeps North Atlantic surface waters saltier, increases density, enhances deep water formation, and strengthens the AMOC (typically by ~2–3 Sv in models under present-day conditions). It also reduces Arctic-to-Atlantic freshwater export via sea ice and liquid water. Paleoclimate simulations (when the strait was closed by lower sea levels) consistently show a stronger AMOC and increased northward heat transport with a Pacific-Atlantic climate “seesaw” (warmer North Atlantic, cooler North Pacific).

Feedback with weakening AMOC:

As the AMOC slows (due to climate-driven freshwater hosing from Greenland melt, increased precipitation, etc.), the BST can weaken or even reverse in extreme cases—exporting saltier Atlantic water to the Pacific instead. This reversal can act as a negative feedback in open-strait scenarios by removing excess freshwater from the Atlantic. Closing the strait removes this potential “safety valve,” so outcomes depend critically on the background state and forcing type.

Tipping Behavior and Hysteresis

AMOC tipping involves bifurcation (saddle-node) behavior: under increasing freshwater forcing (hosing) or warming (polar amplification), the circulation weakens gradually until a critical threshold, then collapses abruptly to a weak/off state. Hysteresis means the system can remain in the collapsed state even after forcing is reduced, requiring a stronger reversal to restart.

In the Soons & Dijkstra study (using the CLIMBER-X Earth System Model of Intermediate Complexity, supported by box models):

Under low additional freshwater flux (or moderate CO₂ scenarios with a still-strong AMOC), closure extends the safe carbon budget and delays or prevents tipping. The AMOC remains stronger longer as CO₂ rises, increasing its resilience.

There is a critical threshold: Roughly when the AMOC has weakened by 16% from pre-industrial (16.4 Sv in their model, corresponding to a critical hosing ~0.16 Sv or specific CO₂-forced weakening). Above this weakening (higher hosing/weaker state), closure reduces the safe budget and can make tipping more likely or accelerate it. The excess freshwater from climate forcing can no longer be efficiently exported, and secondary effects (e.g., increased Arctic sea ice, reduced evaporation, altered surface fluxes) further freshen the North Atlantic.

Box model extensions confirm sensitivity:

Pure freshwater hosing: Closure often has a destabilizing effect (narrower or shifted hysteresis loop).

Temperature-driven forcing (polar amplification): Closure can stabilize if freshwater hosing is limited, because weakening allows a reversal of BST that exports salt; blocking it prevents that freshening pathway.

Results depend on forcing rate, BST parameters, and exact background conditions. Timely closure (while AMOC is strong enough) is essential; mistimed intervention backfires.

Earlier work (e.g., Hu et al. using CCSM) showed that open Bering Strait reduces hysteresis under freshwater forcing (AMOC weakens more gradually without abrupt collapse), while closure enables stronger bistability—relevant to glacial abrupt changes (Dansgaard-Oeschger events).

The 2026 study builds on this by exploring constructed (artificial) closure as an intervention under modern/future anthropogenic forcing.

Practical and Modeling Caveats

Stabilization potential: In moderate scenarios, it could buy time by making the North Atlantic saltier and convection more robust. However, it’s a proof-of-concept; full Earth System Models with higher resolution, dynamic ice, clouds, and biogeochemistry might modify results.

Risks of backfire: If the AMOC is already past or near the critical weakening, closure could trap freshwater in the Atlantic sector, reduce heat/salt exchange, and push the system over the edge.

Uncertainties: AMOC observations show weakening but debate its proximity to tipping. Models vary in sensitivity. The intervention’s effect also interacts with other forcings (CO₂ vs. pure hosing) and rate of change.

Broader impacts: Beyond tipping, closure would disrupt ecosystems (migration, nutrients, fisheries), Indigenous communities, Arctic sea ice dynamics, and Pacific-Arctic heat/freshwater exchange. Geopolitically and logistically daunting (shallow but remote, icy, stormy waters between adversaries).

This radical idea highlights the AMOC’s sensitivity to inter-basin freshwater transports and the potential for targeted (if extreme) interventions.

It does not replace emissions reductions, which address the root freshwater and warming drivers. Further modeling across hierarchies (box → EMIC → GCM) is needed, along with better real-time AMOC monitoring for early warning.

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The effects of a constructed closure of the Bering Strait on AMOC tipping behavior

Closing the Bering Strait artificially could alter AMOC tipping behavior in a state-dependent way: it tends to stabilize and strengthen the circulation when the AMOC is still relatively robust but can destabilize it and accelerate collapse if implemented after substantial weakening.

This is the core finding from the 2026 Science Advances paper by Jelle Soons and Henk Dijkstra (Utrecht University), titled exactly “The effects of a constructed closure of the Bering Strait on AMOC tipping behavior.”

Published: Science Advances, 24 Apr 2026

DOI: 10.1126/sciadv.aeb7887

Vol 12, Issue 17

Authors: Jelle Soons and Henk A. Dijkstra

Abstract

The Atlantic Meridional Overturning Circulation (AMOC) is a major tipping element in the present-day climate and could potentially collapse under sufficient freshwater or CO₂ forcing. While the effect of the Bering Strait on AMOC stability has been well studied, it is unknown whether a constructed closure of this Strait can prevent an AMOC collapse under climate change. Here, we show in an Earth system Model of Intermediate Complexity that an artificial closure of the Strait can extend the safe carbon budget of the AMOC, provided that the AMOC is strong enough at the closure time. Specifically, an equilibrium AMOC under a sufficiently low additional freshwater flux has an increased safe carbon budget given a timely closure of the Strait, while for higher freshwater fluxes (and corresponding weaker AMOC), a closure reduces this budget. This indicates that constructing this closure could be a feasible climate intervention strategy to prevent an AMOC collapse.