EGU24-3457, updated on 08 Mar 2024
https://doi.org/10.5194/egusphere-egu24-3457
EGU General Assembly 2024
© Author(s) 2024. This work is distributed under
the Creative Commons Attribution 4.0 License.

A glimpse into the future: The 2023 temperature extremes in the North Atlantic in the context of longer-term climate change

Till Kuhlbrodt1, Ranjini Swaminathan2, Paulo Ceppi3, and Thomas Wilder1
Till Kuhlbrodt et al.
  • 1National Centre for Atmospheric Science, University of Reading, United Kingdom (t.kuhlbrodt@reading.ac.uk)
  • 2National Centre for Earth Observation, University of Reading, United Kingdom (r.swaminathan@reading.ac.uk)
  • 3Department of Physics, Imperial College London, United Kingdom (p.ceppi@imperial.ac.uk)

In the year 2023, we have seen extraordinary extrema in high sea-surface temperature (SST) in the North Atlantic which are outside the 4-sigma envelope of the 1982-2011 daily timeseries. Here we take a first look at the large-scale, longer-term drivers of these extrema. Earth’s net global energy imbalance (in the 12 months up to September 2023) amounts to +1.9 W/m2 as part of a remarkably large upward trend, ensuring continuous heating of the ocean. However, the regional radiation budget over the North Atlantic does not show signs of a significant step increase from less negative aerosol forcing since 2020 as was suggested elsewhere. While the temperature in the top 100 m of the global ocean has been rising in all basins since about 1980, specifically the Atlantic basin has continued to further heat up since 2016. Similarly, salinity in the top 100 m of the ocean has increased in recent years specifically in the Atlantic basin. Outside the North Atlantic, around 2015 a substantial negative trend for sea-ice extent in the Southern Ocean has begun, leading to record low sea-ice extent in 2023. We suggest analysing the 2023 temperature extremes in the North Atlantic in the context of these recent global-scale ocean changes. Analysing climate and Earth System model simulations of the future, we find that the extreme SST in the North Atlantic and the extreme in Southern Ocean sea-ice extent in 2023 lie at the fringe of the expected mean climate change for a global surface-air temperature warming level (GWL) of 1.5°C, and closer to the average at a 3.0°C GWL. Understanding the regional and global drivers of these extremes is indispensable for assessing frequency and impacts of similar events in the coming years.

How to cite: Kuhlbrodt, T., Swaminathan, R., Ceppi, P., and Wilder, T.: A glimpse into the future: The 2023 temperature extremes in the North Atlantic in the context of longer-term climate change, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-3457, https://doi.org/10.5194/egusphere-egu24-3457, 2024.

Supplementary materials

Supplementary material file

Comments on the supplementary material

AC: Author Comment | CC: Community Comment | Report abuse

supplementary materials version 1 – uploaded on 10 Apr 2024, no comments

Post a comment