Record-shattering Jump in Sea Surface Temperatures in 2023/24 Was Unlikely but Not Unexpected 

Global sea surface temperatures in 2023/24 exceeded the previous record by an unprecedented margin of 0.25 °C. This sudden, unprecedented jump raised concerns that global warming might have accelerated unexpectedly.

The authors use observation-based statistical models to show that such jumps in ocean temperatures can rarely occur due to internal variability and global warming (1-in-512-years event) but are practically impossible without warming.

Moreover, climate models simulate such events with similar likelihoods. These simulations show that such events only occur during an El-Niño and are often accompanied by an especially warm North Atlantic and North Pacific.

In climate models, temperatures revert to the long-term warming trend in the years after such a jump and are thus not a sign of an unexpected acceleration of global warming.

Reference:
Terhaar, J., Burger, F.A., Vogt, L., et al. (2025). Record sea surface temperature jump in 2023–2024 unlikely but not unexpected. Nature, 639, 942-946. https://doi.org/10.1038/s41586-025-08674-z
Nature Editorial. (2025 March 26). Global marine heatwave of 2023–24 was viewed as unlikely but not impossible given current warming [Research Briefing]. Nature. https://doi.org/10.1038/d41586-025-00888-5