Scientists have come up with a radical proposal to help prevent a key ocean current from collapsing – but it could disrupt a key shipping route.
The Atlantic Meridional Overturning Circulation (AMOC) is a vast network of ocean currents which drives warm water northwards through the Gulf Stream.
There is a growing concern that, due to global warming, the AMOC could weaken or even shut down, with some studies even warning of an oncoming collapse this century.
This would likely cause temperatures in the UK to plummet, with winters becoming up to 7°C (12.57°F) colder on average.
But experts believe there’s a way to prevent this happening – and it involves closing the Bering Strait, a 53–mile (82km)–wide international waterway separating Russia and Alaska.
A constructed closure of the Bering Strait would alter the balance of freshwater in the system, acting as a stabiliser to prevent it from collapse, they said.
‘A possible collapse would have a major impact on the global climate, particularly Europe’s, and could be practically irreversible,’ the researchers wrote in the journal Science Advances. ‘Constructing this closure could be a feasible climate intervention strategy to prevent an AMOC collapse.’
However, this strait serves as a critical shipping route connecting Asia and Europe – providing an important shortcut for cargo, energy resources and research vessels.
The proposed closure consists of three separate dams that connect mainland Russia to Alaska via two small islands called the Diomedes
The researchers compared their proposal to the Saemangeum Seawall in South Korea, which is 20 miles (33km) long
For their study the team, from Utrecht University in the Netherlands, used models to simulate how the AMOC would respond in different scenarios.
The key idea in their paper is that the AMOC is very sensitive to how much freshwater is in the system.
The current depends on dense, cold and salty water sinking in the North Atlantic.
Having the Bering Strait open means that fresh Pacific water can flow northwards, diluting the current’s salinity and weakening it.
But closing it would result in a saltier North Atlantic, ensuring the AMOC stays ‘on’ instead of collapsing.
To do this, they propose building a mega–dam across the strait that would completely block water exchange between the Pacific and Arctic Ocean.
This 50–mile (80km) long dam would include a raised barrier above sea level around 330 feet (100m) wide at the top.
The authors argue it is technically feasible because the strait is shallow and relatively narrow, and is comparable to existing projects such as land reclamation or major seawalls.
Studies suggest that the collapse of AMOC could lead to a new ‘Ice Age’ in the Northern Hemisphere as temperatures over Europe plumet and ice encroaches from the Arctic just like the disaster movie ‘The Day After Tomorrow’ (pictured)
The team said their proposal would only be effective if implemented before the AMOC becomes too weakened.
But they warned that this project would have a ‘large impact’ on local ecosystems.
‘Particularly in this regard, we do want to stress that carbon dioxide mitigation efforts are the preferable option to prevent an AMOC collapse,’ they wrote.
‘But if this is not realised, this study showed that a man–made timely closure of the Bering Strait can prevent a collapse of the AMOC under particular climate forcing scenarios. ‘
In the event of an AMOC collapse the Gulf Stream – which is an important part of the system – would also suffer significant, catastrophic effects.
This would mean less warm water reaches Europe, triggering extensive cooling.
Earlier this month, scientists from the University of Bordeaux warned the AMOC is on track to weaken 50 per cent by the end of this century.
Experts previously thought AMOC would only reduce in strength by around 32 per cent over this time period.
This has raised concerns that the world may be unprepared for the rapid climate changes that this dramatic weakening will bring.
In their paper, the researchers said this will trigger ‘significant modifications’ to the global climate in the future.
The slowdown could lead to ‘extensive drying’ in Africa’s drought and famine–stricken Sahel region, according to the experts.
Meanwhile, temperatures in the Northern Hemisphere will plummet as the Gulf Stream fails to bring warm water up from the Tropics.
