A bold and controversial geoengineering proposal suggests that building a massive dam between Alaska and Russia could help prevent the collapse of a vital ocean current. However, while the idea could theoretically stabilize the climate in Northern Europe, scientists warn that the plan is far from a guaranteed fix and carries immense ecological and geopolitical risks.
The Threat: A Collapsing “Conveyor Belt”
The focus of this research is the Atlantic Meridional Overturning Circulation (AMOC). This system acts as a massive underwater conveyor belt, transporting warm, salty water from the tropics toward the North Atlantic. As this water cools and sinks, it drives a circulation pattern that regulates temperatures across Europe, Africa, and the Americas.
The AMOC is currently under threat from global warming due to two primary factors:
1. Rising Temperatures: Warmer North Atlantic waters may fail to cool and sink as they should.
2. Freshwater Influx: Melting ice sheets are pouring fresh water into the ocean, diluting the saltiness required for the water to sink.
If the AMOC collapses, the consequences would be catastrophic: Northern Europe could see plummeting temperatures, North America could face significant sea-level rises, and global food production could be severely disrupted. Recent studies suggest this weakening is happening much faster than previously predicted, potentially slowing by up to 59% by the year 2100.
The Proposal: Closing the Bering Strait
In a new study published in Science Advances, researchers Jelle Soons and Henk Dijkstra explored a radical solution: blocking the Bering Strait to disconnect the Pacific Ocean from the Arctic Ocean.
The logic is based on paleoclimatology. Roughly 3 million years ago, during the mid-Pliocene epoch, a land bridge existed that closed this passage, and the AMOC was significantly stronger during that period. The researchers modeled a scenario where three dams—spanning a 51-mile (82 km) stretch—would be constructed across the strait.
The Results: A Double-Edged Sword
The study found that the effectiveness of such a dam depends heavily on current environmental conditions:
– In a “mild” scenario: If CO2 emissions remain relatively low and the AMOC is only slightly weakened, closing the strait could strengthen the current and help it resist further decline.
– In a “severe” scenario: If the AMOC is already significantly weakened, closing the strait could actually accelerate its collapse.
Because the outcome depends so heavily on existing CO2 levels and the current strength of the current, experts like Jonathan Baker of the U.K. Met Office caution that this is not a “straightforward solution.”
Engineering and Ecological Hurdles
While the physical construction of such dams is technically feasible—comparable in scale to existing massive seawalls in the Netherlands and South Korea—the practical challenges are staggering.
- Extreme Conditions: Unlike existing dams in calm coastal waters, the Bering Strait is a remote region characterized by powerful currents and heavy sea ice.
- Ecological Disruption: Severing the connection between the Pacific and Arctic Oceans would fundamentally alter the exchange of nutrients, heat, and marine life, potentially devastating ecosystems.
- Human Impact: The project would disrupt shipping lanes, fishing industries, and the traditional ways of life for Indigenous communities who rely on the strait.
- Geopolitics: The dam would sit directly between two rival superpowers, making international cooperation and security a massive hurdle.
Conclusion
While the idea of a Bering Strait dam offers a fascinating theoretical tool for climate intervention, it remains a highly unpredictable gamble. Scientists emphasize that while geoengineering might delay a collapse under specific conditions, it does not address the root cause of the crisis; the most effective way to protect the AMOC remains the aggressive reduction of global greenhouse gas emissions.
