Forecast of ocean current collapse divides scientists

A potential imminent collapse of central ocean currents with irreversible consequences was the topic that divided opinions at a climate conference in Nuuk.

By Rasmus Balle Hansen

If we fail to drastically reduce our CO2 emissions, the North Atlantic Ocean currents, known as AMOC, could collapse. If this happens, it could result in a much colder climate in Northern Europe, comparable to Alaska’s. In the worst-case scenario, the collapse could begin as early as 2057.

This is the conclusion of an article published in the scientific journal Nature Communications in July 2023, authored by Peter Ditlevsen, professor at the Niels Bohr Institute at the University of Copenhagen, and Susanne Ditlevsen, professor at the Department of Mathematical Sciences at the same university.

“We need people to take this seriously. We’ll still be here in 30 years,” says Peter Ditlevsen.

The article has since gained significant media attention and headlines worldwide.

However, not all scientists agree with its conclusions. One of the skeptics regarding an imminent collapse is Hjálmar Hátún, an oceanographer at Havstovan – the Faroe Marine Research Institute.

“I think it is extremely unlikely to happen,” says Hjálmar Hátún, who also studies AMOC in his research. He believes the conclusion is overly dramatic but agrees on the importance of reducing CO2 emissions, which have numerous negative impacts on the global climate, including The Greenland Pump, which transports cold water back southward.

AMOC (Atlantic Meridional Overturning Circulation)

The North Atlantic Ocean currents are not just one current but several interconnected streams. They transport warm water northward and cold water southward via deep currents. The Gulf Stream is one of the most well-known, but many other currents collectively form the North Atlantic Ocean circulation.

Hjálmar Hátún oceanographer from Havstovan – Faroe Marine Research Institute.

Photo by: Hjálmar Hátún

Alarmism threatens credibility

At a climate conference in Nuuk earlier this year, Hjálmar Hátún and Peter Ditlevsen met. Both agreed that CO2 emissions must be reduced and that humanity is on a dangerous path. However, they differ in their interpretation of the data, which Peter Ditlevsen claims predicts a collapse of AMOC. They also have different perspectives on the role scientists should play in the climate debate.

“I have never been a climate alarmist,” says Peter Ditlevsen. “But we need to act now, or things will escalate quickly. As a scientist, it is my duty to present my results, even if they may seem activist.”

Peter Ditlevsen, along with 43 other climate scientists, signed an open letter warning about the irreversible consequences of an AMOC collapse, especially for Nordic countries.

Peter Ditlevsen and Hjálmar Hátún met at ‘Conference on climate research, marine enviroment and the UN Decade of Ocean Science for Sustaiable Development,’ which was arranged by DMI and Arctic Hub.

Hjálmar Hátún takes a different stance on the open letter, which he and several colleagues chose not to sign. “When we dramatize and exaggerate, the story becomes one of impending doom. This diminishes the credibility of scientists. We’re shooting ourselves in the foot,” says Hjálmar Hátún, who, during his presentation at the climate conference, encouraged a ‘cool the AMOC’ approach.

“Scientists should only sound the alarm when we are sufficiently certain. We should avoid being overly dramatic, activist, or political. That is not our role,” Hjálmar Hátún emphasizes.

What does an AMOC collapse mean?

A collapse of the North Atlantic currents could have severe consequences, particularly for Nordic countries. Temperatures would drop significantly, while other parts of the world would experience warming. Simultaneously, the risk of extreme weather increases, potentially affecting ecosystems and, in the worst-case scenario, threatening agriculture.

Disagreement over method, not goal

While there are disagreements among scientists, Hjálmar Hátún stresses that differing opinions in the scientific community should not create doubt about science as a whole. He points out that diversity in views is a strength, but the message to the public must remain clear:

“Disagreements in the scientific world can be confusing, especially on a sensitive topic like this. We risk the media turning it into a ping-pong match where the public watches the ball go back and forth without knowing what to believe. But we all agree that CO2 emissions must be reduced.”

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