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https://doi.org/10.5194/egusphere-2026-2110
© Author(s) 2026. This work is distributed under
the Creative Commons Attribution 4.0 License.
https://doi.org/10.5194/egusphere-2026-2110
© Author(s) 2026. This work is distributed under
the Creative Commons Attribution 4.0 License.
Preprints
21 Apr 2026
 | 21 Apr 2026
Status: this preprint is open for discussion and under review for Ocean Science (OS).

Opinion: The AMOC is weakening – time to take the evidence seriously

Stefan Rahmstorf and Levke Caesar

Abstract. The Atlantic Meridional Overturning Circulation (AMOC) is a critical component of the climate system. Climate models have long predicted a slowing of the AMOC due to anthropogenic forcing, with a risk of passing tipping points in the future. The question of whether the AMOC is already weakening in response to global warming is still somewhat controversial. Continuous monitoring is only available for the past two decades, a period too short to tease apart contributions of natural variability and climate change. Reconstructions of AMOC strength going back further in time have different limitations which are debated in the literature. Here we review the state of this discussion. We conclude that the balance of multiple lines of evidence strongly supports a past and ongoing AMOC slowing in response to global warming.

How to cite. Rahmstorf, S. and Caesar, L.: Opinion: The AMOC is weakening – time to take the evidence seriously, EGUsphere [preprint], https://doi.org/10.5194/egusphere-2026-2110, 2026.
Received: 13 Apr 2026 – Discussion started: 21 Apr 2026
Publisher's note: Copernicus Publications remains neutral with regard to jurisdictional claims made in the text, published maps, institutional affiliations, or any other geographical representation in this paper. While Copernicus Publications makes every effort to include appropriate place names, the final responsibility lies with the authors. Views expressed in the text are those of the authors and do not necessarily reflect the views of the publisher.
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Stefan Rahmstorf and Levke Caesar

Status: open (until 16 Jun 2026)

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Stefan Rahmstorf and Levke Caesar
Stefan Rahmstorf and Levke Caesar
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Short summary
The Atlantic Ocean circulation has a big impact on climate, not only on European temperatures. There has been a longstanding concern that it could slow down or even shut down in response to global warming. While climate models predict that, it is debated whether a slowing is already underway. Here we discuss the available data and conclude that it is very likely that indeed the circulation is already slowing down.
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