Sea levels are just the start of how climate change will upend the ocean. Rising temperatures are also threatening a critical artery that runs through the ocean known as the Atlantic Meridional Overturning Circulation, or AMOC. This current, in short, sends warm water northwards and dumps colder water southwards in a giant loop, massively influencing the world’s weather systems along the way. 

If temperatures keep soaring, scientists fear that AMOC could collapse — and with it, climate patterns across the globe. Temperatures in Europe would plunge without the injection of warm water it brings. Rainfall in the tropics would be disrupted. And sea levels on the US east coast would rise.

To save AMOC from demise, two researchers have proposed a daring Hail Mary: building a giant dam across the Bering Strait, the channel that separates Alaska from Siberia, to stop the proverbial bleeding. As outrageous as it sounds, the megaproject could in theory stabilize the ocean current, according to the findings of a new study they published in the journal Science Advances. 

Jelle Soons, a researcher from Utrecht University and one of the study’s two authors, stressed that the proposal was a “proof of concept,” but told the Financial Times that building the dam could be a “possible measure in a worst-case scenario.”

In their research, Soons and his colleague Henk A. Dijkstra focused on the Bering Strait because it’s through this choke point that AMOC pumps fresh water from the Pacific, then into the Arctic Ocean, and then finally into the Atlantic. Their view of the strait’s importance was buoyed by another study that found that AMOC was stronger three million years ago when the Bering Strait was a land bridge, forming a natural dam of sorts.

Running computer simulations, they found that a dam today would stymy the flow of fresh water from the Arctic Ocean into the Atlantic. That would keep the Atlantic salty, stabilizing the flow across the AMOC broadly.

For this to work, though, the dam would need to be constructed at just the right moment. If it’s built while the AMOC is still strong, then the dam would help it stay healthy, the study found. But if it’s built when AMOC is weak, it could accelerate it towards collapse, the FT noted. While it’s clear the AMOC is weakening, there’s still significant debate over its current health and how close it is to collapse.

The authors gladly concede that the engineering details of actually constructing a dam over fifty miles long is beyond their and the paper’s remit. As are other questions, like how it would impact the migration routes of aquatic life, or the shipping routes of huge oil tankers, or what would it entail for always-testy US-Russian relations, the FT cautioned.

Perhaps it’s for the best that the dam remains a thought-provoking proof-of-concept, and not the blueprint for climate action, was the opinion of the UK’s Met Office.

“The Met Office does not advocate geoengineering solutions to climate change, which can often bring dramatic and unintended consequences,” a spokesperson told the FT. ”Fighting to stave off every fraction of a degree rise of global temperature is the more sustainable and pragmatic approach.”

As it happens, the Bering Strait scheme isn’t the only desperate climatological option that involves building a gargantuan aquatic structure. Engineers have also proposed immuring the Thwaites “Doomsday” glacier in Western Antarctica in an over 60 mile long curtain that blocks out warm water to prevent it from melting.

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