The warm Pliocene: Bridging the geological data and modelling communities
© Author(s) 2022. This work is distributed under
the Creative Commons Attribution 4.0 License.

Northern Hemisphere ice sheets during the M2 Pliocene glacial

Daniel Hill and Aisling Dolan
Daniel Hill and Aisling Dolan
  • University of Leeds, School of Earth and Environment, Leeds, United Kingdom of Great Britain – England, Scotland, Wales (eardjh@leeds.ac.uk)

The large glacial period that immediately precedes the mid-Pliocene Warm Period (mPWP) is a ~0.6‰ benthic oxygen isotope shift at 3.3Ma, known as M2. The excursion is roughly equivalent to 60m of sea level drop or 40msle (metres sea level equivalent) more ice than today. However, there is significant uncertainty in both these values and the potential locations of any large volumes of ice. Previous modelling studies have either used Last Glacial Cycle analogues for the M2 ice sheets or failed to reproduce the large Northern Hemisphere ice sheets implied by global ice volume proxies.


Here we present new climate and ice sheet models simulating the M2 glacial period, by lowering Pliocene atmospheric carbon dioxide concentrations and selecting specific Pliocene orbital forcing. These climates are sufficiently cold to produce ice sheets in North America and northern Europe within our modelling framework. The largest components of these ice masses are centred over regions with significant landscape differences between Pliocene and present day, including the Hudson Bay, Canadian Archipelago and Barents Sea. This suggests that the M2 glacial may have had very different initiation locations to the most recent glacial cycles and that Pliocene palaeogeographic changes may be key to understanding the M2 glacial.

How to cite: Hill, D. and Dolan, A.: Northern Hemisphere ice sheets during the M2 Pliocene glacial, The warm Pliocene: Bridging the geological data and modelling communities, Leeds, United Kingdom, 23–26 Aug 2022, GC10-Pliocene-63, https://doi.org/10.5194/egusphere-gc10-pliocene-63, 2022.