Matos et al. (2025) Modeling the Late Pliocene with AWI-CM3 as a contribution to PlioMIP3 core experiments

Identification

• Journal: Global and Planetary Change
• Year: 2025
• Date: 2025-11-29
• Authors: Fernanda DI Alzira Oliveira Matos, Christian Stepanek, Sven Harig, Jan Streffing, Qiong Zhang, Zhenqian Wang, Katherine Power, Tido Semmler, Dmitry Sidorenko, Patrick Scholz, Sergey Danilov, Paul Gravis, Gerrit Lohmann
• DOI: 10.1016/j.gloplacha.2025.105196

Research Groups

• Alfred Wegener Institute, Helmholtz Centre for Polar and Marine Research, Bremerhaven, Germany
• Department of Physical Geography, Stockholm University, Stockholm, Sweden
• Department of Biology, University of Copenhagen, Copenhagen, Denmark
• Met Eireann, Dublin, Ireland
• Institute for Environmental Physics, University of Bremen, Bremen, Germany
• School of Geography, Earth and Atmospheric Sciences, University of Melbourne, Melbourne, Victoria, Australia

Short Summary

This study presents the first application of the AWI-CM3 climate model for Late Pliocene (3.205 Ma BP) simulations within the PlioMIP3 framework, demonstrating a significantly warmer climate with pronounced polar amplification, an intensified hydrological cycle, and a reorganized ocean circulation, notably a strengthened Atlantic Meridional Overturning Circulation.

Objective

• To present the PlioMIP3 core simulations for the pre-industrial control (PI) and the Late Pliocene (LP) based on the AWI Climate Model, Version 3 (AWI-CM3).
• To document the methods devised to generate AWI-CM3 model setups for paleoclimate research under geographies that differ from the modern reference state.
• To analyze LP large-scale climate patterns in comparison to the PI.

Study Configuration

• Spatial Scale: Global. Ocean model (FESOM2.5) uses an unstructured mesh with a nominal 1° horizontal resolution, refined to 1/3° near the Equator and 24 km north of 50°N. Atmospheric model (OpenIFS) uses a cubic octahedral truncation TCo95L91, corresponding to a 100 km horizontal resolution with 91 vertical layers.
• Temporal Scale: Late Pliocene (Marine Isotope Stage KM5c, 3.205 Ma BP) and Pre-Industrial (PI, 1850 CE). Simulations were run for 700 years (PI) and 2000 years (LP), with the final 200 years used for analysis.

Methodology and Data

• Models used:
  • AWI Climate Model, Version 3 (AWI-CM3)
  • Ocean component: Finite volumE Sea-ice Ocean Model version 2.5 (FESOM2.5)
  • Atmospheric component: OpenIFS (version 43r3v2)
  • Coupler: Ocean, Atmosphere, Sea Ice, Soil Model Coupling Toolkit, version 4 (OASIS-MCT4)
  • Auxiliary modules: Runoff Mapper, XML Input/Output Server (XIOS)
• Data sources:
  • PRISM4 (mid-Piacenzian) paleoenvironmental reconstruction (Dowsett et al., 2016; Haywood et al., 2016) for Late Pliocene boundary conditions (land-sea mask, land elevation, ice sheets, lakes, soils, vegetation).
  • Polar Hydrographic Climatology, version 3.0 (PHC3.0; Steele et al., 2001) for initial ocean temperature and salinity fields.
  • PMIP4/CMIP6 piControl protocol for Pre-Industrial state.
  • Proxy evidence for Late Pliocene atmospheric CO2 concentration (400 ppmv).

Main Results

• The Late Pliocene climate is approximately 4 °C warmer than the pre-industrial reference, with land warming exceeding ocean warming by a factor of 1.2.
• Polar amplification is pronounced, with Antarctic surface air temperature anomalies exceeding 6 °C and Arctic anomalies reaching 4 °C to 5 °C.
• Global mean precipitation increases by 0.31 mm d⁻¹, indicating an intensified hydrological cycle.
• The global mean ocean surface warms by about 3.06 °C.
• Contrasting salinity trends are observed, with salinization of the North Atlantic (+3 PSU) and freshening of the Arctic (–2.5 PSU) and Indian (–1 PSU) Oceans.
• The Atlantic Meridional Overturning Circulation (AMOC) strengthens by about 8 Sv (from 16.6 Sv in PI to 25.2 Sv in LP).
• The Pacific Meridional Overturning Circulation (PMOC) remains inactive (near 1.3 Sv).
• The global Antarctic Bottom Water (AABW) cell is substantially reduced (11 Sv weaker relative to PI, from 17.2 Sv to 6 Sv).
• Global sea-ice extent is reduced, halved in the Southern Hemisphere with respect to PI.
• Enhanced northward ocean heat transport is observed in the North Atlantic.
• The model reproduces large-scale climate features of the Late Pliocene inferred from proxy records and the PlioMIP2 ensemble.

Contributions

• Presents the first application of the AWI-CM3 coupled climate model for simulating the Late Pliocene climate under PlioMIP3 boundary conditions, including a detailed methodology for model adaptation to paleogeographies.
• Contributes core simulations (Pre-Industrial and Late Pliocene) to the PlioMIP3 framework, facilitating future model intercomparison.
• Quantifies AWI-CM3's climate sensitivity to Pliocene boundary conditions, positioning it among the warmer PlioMIP2 ensemble members with an equilibrium climate sensitivity of approximately 4 °C.
• Highlights the pivotal role of tectonic boundary conditions (e.g., Bering Strait closure) in shaping ocean circulation, particularly the strengthening of the AMOC in the Late Pliocene, which contrasts with projected weakening under future global warming scenarios.
• Provides a paleoclimate-informed assessment of uncertainties in modeled warm climates and emphasizes the complexity of drawing direct analogies between Pliocene and future warming.

Funding

• INSPIRES (International Science Program for Integrative Research in Earth Systems) at the Alfred Wegener Institute, Helmholtz Centre for Polar and Marine Research.
• DAAD (German Academic Exchange Service) for F.D.A.O.M.'s research stay at Stockholm University.
• European Research Council grant "i2B" (Into the Blue; grant no. 101118519).
• Jülich Supercomputing Centre (JSC) and the German Climate Computing Centre (DKRZ) for providing computing time on the supercomputers JUWELS and LEVANTE.

Citation

@article{Matos2025Modeling,
  author = {Matos, Fernanda DI Alzira Oliveira and Stepanek, Christian and Harig, Sven and Streffing, Jan and Zhang, Qiong and Wang, Zhenqian and Power, Katherine and Semmler, Tido and Sidorenko, Dmitry and Scholz, Patrick and Danilov, Sergey and Gravis, Paul and Lohmann, Gerrit},
  title = {Modeling the Late Pliocene with AWI-CM3 as a contribution to PlioMIP3 core experiments},
  journal = {Global and Planetary Change},
  year = {2025},
  doi = {10.1016/j.gloplacha.2025.105196},
  url = {https://doi.org/10.1016/j.gloplacha.2025.105196}
}