AMOC

stands for Atlantic Meridional Overturning Circulation and is a horror scenario regularly good for a headline. AMOC means that the warming Gulf Stream is "drying up," with devastating consequences for the climate on the European continent.

In a recent article in Science Advances, "Physics-based early warning signal shows that AMOC is on tipping course," René M. van Westen, Michael Kliphuis, and Henk A. Dijkstra try to predict the date of collapse for the AMOC. It is comforting that their simulations show that the tipping point will occur no earlier than 2100. Still, they also warned that their stimulation was incomplete due to the lack of data, and the tipping may occur earlier or later (?).

However, there are reasons to take these predictions with a grain of salt since the Earth system is currently blowing up all models with its incredibly rapid heating.

2023 was a year with air and ocean temperatures far beyond all normal fluctuations, and 2024 "promises" to be even hotter. March of this year in Germany was four full degrees Celsius warmer than the long-term average from 1961 to 1990. 

Highest temperatures on April 6, 2024

Nine days ago, we beat all the temperature records.

The thick grey line is the average temperature of the Atlantic surface over a year
up to 2022. The thick red line is the temperature anomaly observed in 2023
 that is continuing in 2924 (brown line) (©Nahel Belgherze)

The oceans are even hotter than the air. Extreme weather expert Maximiliano Herrera said, "We are entering uncharted territory regarding heat records. Nothing compares to what we've been experiencing since 2023."

There will most likely be even more extreme rainfall events this year than in the catastrophic year of 2023. At the same time, the polar ice is melting much faster and regenerating much more slowly than in the past. This, among other things, makes the seawater in the polar regions less salty.

The Gulf Stream transports warm tropical water into the north.
After cooling, the water streams back into the southern Atlantic.
a)During the last ice age. b) The present situation (©van Westen et al.)

This situation could trigger the massive planetary catastrophe of AMOC much faster than previously estimated. Temperatures in northern Europe would drop dramatically within a very short time.

Scandinavia and the British Isles experience permafrost,
while the average annual temperature in the continental coastal regions
stays below 0 °C. (©van Westen et al.)

Elsewhere on the globe, monsoon regions would shift, and sea levels would rise abruptly, for example, on the US Atlantic coast. As climate expert Stefan Rahmstorf stated, "All in all, there would be devastating consequences for humanity and ecosystems in the sea and on land."

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