New research on Atlantic Ocean currents misrepresented online
- Published on March 17, 2025 at 22:33
- 6 min read
- By Manon JACOB, AFP USA
Copyright © AFP 2017-2025. Any commercial use of this content requires a subscription. Click here to find out more.
New scientific research claims ocean currents are "stable," states Anthony Watts in a February 28, 2025 article on his website.
"The Atlantic Meridional Overturning Circulation is not collapsing, is not slowing catastrophically, and is not about to trigger an Ice Age. The latest scientific research confirms what observational data has shown for decades: AMOC variations are natural, and there is no impending crisis," said Watts, who has previously been fact-checked by AFP.
The Climate Change Dispatch website, a frequent source of disinformation on environmental issues, has repeatedly hosted articles that decry "alarm" on climate change and its impacts, including about the ocean's conveyor belt.
The Atlantic Meridional Overturning Circulation (AMOC) is a complex system of ocean currents, including the Gulf Stream, which drives heat from warmer regions to the north and is therefore crucial to living conditions in the Arctic, as it carries nutrients necessary to sustain ocean life (archived here).
The weakening of the system is one of the tipping points that concerns scientists because of the cascading effects it could trigger.
Watts centers his article around two peer-reviewed studies published in January and February 2025 (archived here and here) to back his claim of "stable" ocean currents in the Atlantic that he says are "extremely unlikely to collapse in the foreseeable future." He claims the papers did not receive media coverage due to them casting doubt on climate change and its impacts on AMOC, despite multiple news outlets reporting on the findings, including AFP.
And climate scientists, including one of the authors whose work is referenced in the blog post, said Watts misrepresented the findings on the topic.
"Our study demonstrates that while a collapse of the AMOC is unlikely this century, a weakening is very likely -- a change with serious consequences that Antony Watts' article fails to acknowledge," Jonathan Baker (archived here), an ocean scientist at the Met Office in the United Kingdom and corresponding author of one of the studies, told AFP on March 4.
Weakening currents
Baker said if ocean current systems are weakened, it likely will alter global rainfall patterns -- increasing the risks of both droughts and floods -- especially along the East Coast of the United States, accelerate sea level rise, disrupt marine ecosystems and reduce the ocean's ability to absorb carbon dioxide.
Such impacts have been researched before (archived here and here).
"Our finding that the AMOC is very likely to weaken this century aligns with a broad body of literature," Baker said.
German oceanographer and climatologist, Stefan Rahmstorf (archived here), a leading scientist in the study of AMOC, said that part of the confusion online originated from the study authors using a different definition for what would constitue a collapse of AMOC -- namely a total cessation anywhere in the North Atlantic. "So, in their definition the AMOC does not collapse," he said on March 14.
"At the core, there is just a disagreement over" the terminology used, he explained, with the study authors, themselves, confirming a weaker AMOC would have major climate impacts.
The study does not fundamentally differ from earlier work on the subject, independent scientists told AFP.
Historical reconstruction
There was a lack of proper measurements of the ocean networks prior to 2004, so scientists seeking to study longer patterns in changes to the AMOC must examine indirect data such as ocean salinity patterns or paleoclimatic proxy data.
In the case of the other study highlighted by Watts (archived here), Jens Terhaar of the University of Bern (archived here) and his team used ocean surface heat loss data.
They found an absence of decline in the AMOC since 1960, according to a reanalysis based on different simulation models.
This study does not mean that the AMOC "will not decline or collapse" in the future, Terhaar previously told AFP. "We expect the AMOC to weaken very soon and the consequences (of this weakening) to be severe."
Rahmstorf also said the study's findings were taken out of context by Watts.
The use of proxy data to reconstruct the evolution of ocean currents between 1960 and now makes it complex to fully assess if a weakening has already happened outside of the normal range of variability.
These are "model results, and the surface fluxes of these reanalysis models are known to be particularly uncertain," Rahmstorf noted.
Call for further research
There is no current scientific consensus on when the predicted AMOC weakening is likely to happen, but the sixth assessment report by the UN's Intergovernmental Panel on Climate Change (IPCC), expressed "medium confidence that the Atlantic Meridional Overturning Circulation will not collapse abruptly before 2100" (archived here).
In October 2024, a consortium of the most prominent scientists on the topic urged in an open letter for more research on AMOC and its behavioral shifts.
"Recent research since the last IPCC report does suggest that the IPCC has underestimated this risk and that the passing of this tipping point is a serious possibility already in the next few decades," they said in a statement (archived here).
One of the letter signatories, British paleoceanographer David Thornalley (archived here), told AFP on March 14 that while there are "numerous lines of indirect evidence for a weakening of AMOC" as well as "some counter evidence," scientists agree that AMOC is likely to weaken substantially in the future.
Even without concensus on the potential existing changes in Atlantic currents, scientists agree the primary driver is global warming.
"The basic physics suggest this should be the case and all IPCC models show this," Thornalley said. "There is debate about just how fast and how much this may be, but in almost all cases the climate impacts are significant, and we want to avoid them."
Earth's warming climate triggers a series of effects on ocean ecosystems including the melting of ice sheets and glaciers, sea level rise, ocean acidification and coral reef bleaching, which all underscore the pressing need to reduce greenhouse gas emissions to limit further global warming.
AFP has investigated other false and misleading claims about the impacts of anthropogenic warming on our oceans.
Is there content that you would like AFP to fact-check? Get in touch.
Contact us
