An ambitious engineering project looms on the horizon: constructing a dam between Alaska and eastern Russia. This innovative proposal aims to combat the dire consequences of a weakening ocean current, and is under serious consideration at a prominent conference this week.

The seeds of this groundbreaking idea were sown by Jere Soon and his collaborator Henk Dijkstra, a researcher focused on the Atlantic Meridional Overturning Circulation (AMOC) at Utrecht University, Netherlands. This current system, including the Gulf Stream, is crucial for keeping northern Europe warmer than its geographical latitude would suggest.

Current data indicates that the AMOC is weakening. The potential effects of its collapse are uncertain, but many models hint at a possible significant drop in temperatures across Northern Europe.

The concept was inspired by the Pliocene era, when sea levels were considerably lower and a land bridge existed where the Bering Strait now lies. During this time, simulations revealed a stronger AMOC due to the presence of this land bridge. “I thought: can we replicate this?” says Soon.

To explore the implications of such dam construction, Soon and Dijkstra simulated various AMOC scenarios, adjusting the construction date and freshwater levels.

In a recent study, Soons and Dijkstra obtained mixed results: in certain scenarios, dams seemed to enhance the AMOC, while in others, they produced the opposite effect. It’s important to note that these findings were derived from relatively basic, low-resolution models.

On May 5, Dr. Soons presented significant research results at the European Geosciences Union General Assembly in Vienna, Austria. Simulations were re-evaluated using a supercomputer that employed advanced climate models. The results indicate that closing the strait could reinforce the AMOC, particularly if dams are constructed by 2050. “I was surprised at how robust the recovery was,” Soon remarked.

The Bering Strait, at its deepest point, measures only 59 meters and features two small islands in the middle, suggesting the viability of constructing a barrier. Ed McCann, former president of the Japan Society of Civil Engineers and current head of expedition engineering, suggests that rather than concrete, using flotation machinery to build barriers with rock and dredged sand would be most efficient. “This type of construction is straightforward, albeit large-scale and costly,” he commented via email.

Jonathan Rosser, a researcher at the London School of Economics, finds the study intriguing. However, he emphasizes that due to the AMOC’s complexities, we cannot fully predict the outcomes of such interventions. “These drastic measures come with significant uncertainty.”

Suhn concurs, cautioning that while dam construction may benefit Northern Europe, it could lead to adverse effects elsewhere, such as altered rainfall patterns. “Are we ready to take this seriously? I don’t think we’re there yet,” he concluded.

This isn’t the first consideration of constructing gigantic ocean dams to address climate change. In 2020, Sjoerd Groeskamp from the Royal Netherlands Marine Institute proposed the “Northern European Enclosure Dam,” designed to create barriers around the sea between the UK and mainland Europe, protecting low-lying areas from rising seas.

Such dams would undoubtedly impact not only the climate but also marine mammal migration, tidal patterns, and transport access to isolated regions. Mr. Soons noted that he has explored ideas like constructing partial barriers or lowering them to a depth of approximately 10 meters. These concepts are “interesting,” he said, though he has yet to thoroughly analyze their feasibility.