More than 40 climate scientists are urging Nordic ministers to prevent global warming from causing a major change in an Atlantic Ocean current, which could trigger abrupt shifts in weather patterns and damage ecosystems.
A collapse of the Atlantic Meridional Overturning Circulation (Amoc), a system of ocean currents that transports warm water into the North Atlantic and provides Europe with its mild climate, could put living conditions for people in the Arctic region and beyond at risk, according to the scientists.
“Such an ocean circulation change would have devastating and irreversible impacts, especially for Nordic countries, but also for other parts of the world,” the scientists said in a letter to the Nordic Council of Ministers, which comprises of five countries, including Denmark and Sweden, and three autonomous territories.
The letter urges the council to actions that could involve calling for global greenhouse gas emission cuts. Several studies have suggested that the risk of the Atlantic current changing has been greatly underestimated, the scientists said, adding there was a serious possibility of passing the tipping point in the next few decades.
“If Britain and Ireland become like northern Norway, [that] has tremendous consequences,” said Peter Ditlevsen of the University of Copenhagen, a signatory of the letter.
A collapse of the ocean-current system would increase cooling of the Northern hemisphere, raise Atlantic sea levels, drop precipitation over Europe and North America, and shift monsoons in South America and Africa, according to the Britain’s Met Office.
Global subsidies for fossil fuels reached a record $7,000bn in 2022, according to the International Monetary Fund. Such subsidies show there is no credible effort to prevent such a climate disaster, said Stefan Rahmstorf from Germany’s Potsdam Institute for Climate Impact Research.
Amoc is a large system of ocean currents which transports warm water from the tropics northwards into the North Atlantic.
As the atmosphere warms due to increased greenhouse gas emissions, the surface ocean beneath retains more heat. A potential collapse of the system could have severe consequences.
Climate models have shown that the Amoc is at its weakest in more than 1,000 years. However, it has not been known whether the weakening is due to a change in circulation or it is to do with the loss of stability.
Other models have said the Amoc will weaken over the coming century, but a collapse before 2100 is unlikely.
It was revealed in August that Met Éireann forecasters were briefed on the “profound impacts” of the possible collapse of Amoc.
They were given guidance on how best to communicate the risks and how the Amoc was at its weakest in over a millennium. Forecasters were told a large cold pool of water, sometimes referred to as the ‘cold blob’, had been observed in North Atlantic waters in recent decades as part of the system weakening.
The guidance note said: “The northern part of the North Atlantic where the cold pool has been observed is the only global region which has cooled as the rest of the world has warmed due to climate change.”
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