Early stage of global warming

Satellite data show an ocean warming pattern that is amplified over the subtropics. Climate simulations suggest that this pattern is an early signature of warming ocean, and there is a long way for the ocean to warm up. In the future, the warming signal will be amplified at subpolar ocean.
Early stage of global warming

The satellite observed sea surface temperature recently reached a milestone temporal coverage of 40 years. This data provides a good opportunity to evaluate the extent of the anthropogenic warming. It documents a strong warming of the subtropical ocean and a cooling of the tropical eastern Pacific Ocean. This pattern was widely interpreted as a manifestation of the Pacific Decadal Oscillation. However, we find that the observed warming/cooling pattern is dynamically consistent with where the surface water converges (subtropical gyres, downwelling) and diverges (subpolar gyres, upwelling), therefore it can be attributed to ocean dynamics.

Features of early-stage (subtropical amplified) and equilibrium (subpolar amplified) ocean warming.

We show that the observed ocean warming pattern belongs to a forced response, which only manifests itself at the very early stage of CO2 forcing when the heating anomaly is limited in the upper ocean. Long-term warming of the subpolar ocean, where surface water connects the deep ocean, will have a greater amplitude than it would on the subtropics.

Features of early-stage (subtropical amplified) and equilibrium (subpolar amplified) ocean warming from a zonal and vertical perspective.

 Our results point out a serious fact: even though the ocean surface temperature set another new record high this year, the current warming is still in its infancy. Ocean temperature will keep rising for thousands of years, even if greenhouse gas concentrations stop rising right now. The committed, but delayed warming over the subpolar ocean will have strong impact on the ocean-atmosphere circulation and has the potential to cause a sea level rise of more than 10 meters.


Yang, H., Lohmann, G., Stepanek, C. et al. Satellite-observed strong subtropical ocean warming as an early signature of global warming. Commun Earth Environ 4, 178 (2023). https://doi.org/10.1038/s43247-023-00839-w

Related News:


Please sign in or register for FREE

If you are a registered user on Nature Portfolio Earth and Environment Community, please sign in