Future-proofing interpretations of the Paris Agreement’s limit of well below 2 °C

The Paris Agreement’s ‘well below 2 °C’ target is often interpreted as holding warming below 2 °C with a probability in the 66–90% range. We argue that such interpretations are not future-proof as decreasing uncertainties with time will allow temperatures to approach 2 °C later in the century. We show how referring to median warming can resolve this issue and illustrate how past probabilistic target interpretations would translate to a median 1.65–1.8 °C warming limit range.

Lamboll, R.D., Rogelj, J. Future-proofing interpretations of the Paris Agreement’s limit of well below 2 °C. Nat. Clim. Chang. (2026)
https://doi.org/10.1038/s41558-026-02685-y