11 Sep 2023
 | 11 Sep 2023
Status: this preprint is open for discussion and under review for Climate of the Past (CP).

Can we reliably reconstruct the mid-Pliocene Warm Period with sparse data and uncertain models?

James Douglas Annan, Julia Catherine Hargreaves, Thorsten Mauritsen, Erin McClymont, and Sze Ling Ho

Abstract. We present a reconstruction of the surface climate of the mid-Pliocene Warm Period (mPWP), specifically Marine Isotope Stage (MIS) KM5c or 3.205 Ma. We combine the ensemble of climate model simulations which contributed to the PlioMIP projects, with compilations of proxy data analyses of sea surface temperature (SST). The different data sets we considered are all sparse with high uncertainty, and the best estimate annual global mean surface air temperature (SAT) anomaly varies from 1.0 up to 4.7 °C depending on data source.

We argue that the latest PlioVAR analysis of alkenone data is likely more reliable than other data sets we consider, and using this data set yields a SAT anomaly of 3.6 ± 1.0 °C, with a value of 2.8 ± 0.9 °C for SST (all uncertainties are quoted at one standard deviation). However, depending on the application, it may be advisable to consider the wider range to account for structural uncertainty. The regional scale information in the reconstruction may not be reliable as it is largely based on the patterns simulated by the models. Nevertheless, despite the uncertainties, there is some indication that polar amplification may be underestimated in the models.

James Douglas Annan et al.

Status: open (until 06 Nov 2023)

Comment types: AC – author | RC – referee | CC – community | EC – editor | CEC – chief editor | : Report abuse

James Douglas Annan et al.

James Douglas Annan et al.


Total article views: 282 (including HTML, PDF, and XML)
HTML PDF XML Total BibTeX EndNote
204 70 8 282 6 7
  • HTML: 204
  • PDF: 70
  • XML: 8
  • Total: 282
  • BibTeX: 6
  • EndNote: 7
Views and downloads (calculated since 11 Sep 2023)
Cumulative views and downloads (calculated since 11 Sep 2023)

Viewed (geographical distribution)

Total article views: 272 (including HTML, PDF, and XML) Thereof 272 with geography defined and 0 with unknown origin.
Country # Views %
  • 1
Latest update: 03 Oct 2023
Short summary
We have created a new global surface temperature reconstruction of the climate of the mid-Pliocene Warm Period, representing the period roughly 3.2 million years before the present day. We estimate that the globally averaged mean temperature was around 3.6 °C warmer than it was in pre-industrial times, but there is significant uncertainty on this value.