New SWEET paper on the HadGEM3 mid-Pliocene simulation published

A new SWEET paper has today been published in Climate of the Past:

Williams, C. J. R., Sellar, A. A., Ren, X., Haywood, A. M., Hopcroft, P., Hunter, S. J., Roberts, W. H. G., Smith, R. S., Stone, E. J., Tindall, J. C., and Lunt, D. J.: Simulation of the mid-Pliocene Warm Period using HadGEM3: experimental design and results from model–model and model–data comparison, Clim. Past, 17, 2139–2163,, 2021.


– Brand new simulation of the mid-Pliocene Warm Period (~3 million years ago) using the latest version of the UK’s physical climate model, HadGEM3-GC31-LL, is presented.

– This period is the last time atmospheric CO2 was equivalent to today and, with temperatures much higher globally and especially at high latitudes, provides a possible analogy to future climate change.

– Results from the simulation firstly suggest much warmer and wetter conditions than the pre-industrial era, and with the greatest warming occurring over high-latitude and polar regions. The global mean surface air temperature anomaly at the end of the Pliocene simulation is 5.1°C.

– Secondly, up to a certain level of warming, this warming results in a better agreement with available proxy data, however the “sweet spot” appears to be the previous CMIP5 generation of the same model, HadGEM2-AO.

– Lastly, when compared to other Pliocene simulations from other models, HadGEM3-GC31-LL is one of the warmest and wettest models.