PlioMIP2 (CMIP6/PMIP4) Simulations with CESM2 and CESM1(CAM4 and CAM5)

The CESM PlioMIP2 project, completed as part of CMIP6 and PMIP4 by Bette Otto-Bliesner, Ran Feng, Esther Brady and Nan Rosenbloom, is a set of published simulations to understand Pliocene climate variability, similarities and dissimilarities with pre-Industrial, and model skills in simulating this period (3.2Ma). There are two sets of experiments: CMIP6/PMIP4 tier 1 baseline simulations of preindustrial and mid-Pliocene, and tier 2 sensitivity experiments. These simulations use experimental protocols from the Pliocene Model Intercomparison Project phase 2 (PlioMIP2) (Haywood et al., 2016). 

The CMIP6/PMIP4 PlioMIP2 Tier 1  (midPliocene-eoi400) simulations are performed with the atmosphere-ocean-land-sea ice coupled CESM1(CAM4), CESM1.2(CAM5), and CESM2 at the nominal 1-degree latitude/longitude resolution. Land model is configured with the active carbon-nitrogen cycle, hence, with prognostic leaf area index and gross productivity. Land-only simulations were performed first to spin up the deeper soil carbon reservoir prior to the full simulations. These simulations use the PRISM4D boundary conditions (Dowsett et al., 2016). 

Further details are provided in the papers below:

  • Feng, R., Otto-Bliesner, B. L., Brady, E.C., & Rosenbloom, N. (2020). Increased climate response and Earth system sensitivity from CCSM4 to CESM2 in mid-Pliocene simulations. Journal of Advances in Modeling Earth Systems, 12, e2019MS002033.
  • Haywood, A. M., Dowsett, H. J., Dolan, A. M., Rowley, D., Abe-Ouchi, A., Otto-Bliesner, B., Chandler, M. A., Hunter, S. J., Lunt, D. J., Pound, M., and Salzmann, U.: The Pliocene Model Intercomparison Project (PlioMIP) Phase 2: scientific objectives and experimental design, Clim. Past, 12, 663–675,, 2016.
  • Dowsett, H., Dolan, A., Rowley, D., Moucha, R., Forte, A. M., Mitrovica, J. X., Pound, M., Salzmann, U., Robinson, M., Chandler, M., Foley, K., and Haywood, A.: The PRISM4 (mid-Piacenzian) paleoenvironmental reconstruction, Clim. Past, 12, 1519–1538,, 2016.

The Tier 2 sensitivity simulations are all performed with CESM2 at resolutions consistent with the baseline Tier 1 CESM2 preindustrial control (piControl) and PlioMIP2 mid-Piacenzian (midPliocene-eoi400) simulations. Tier 2 simulations currently include three experiments all prescribed with preindustrial vegetation distribution and ice sheets, but factoring different combinations of CO2, topography and land/sea mask: piControl.400 with CO2 of 400 ppm with all else set to preindustrial, midPliocene-eo400 with CO2 of 400 ppm and mid-Piacenzian topography and land-sea mask, and midPliocene-eo280 with CO2 of 280 and mid-Piacenzian topography and land-sea mask. 

Further details are provided in the paper below:

  • Feng, R., Bhattacharya, T., Otto-Bliesner, B.L., Brady, E.C., Haywood, A.M., Tindall, J.C., Hunter, S.J., Abe-Ouchi, A., Chan, W.L., Kageyama, M. and Contoux, C., 2022. Past terrestrial hydroclimate sensitivity controlled by Earth system feedbacks. Nature communications, 13(1), p.1306.

We kindly ask that you cite the relevant papers and acknowledge the PaleoclimateWG and NSF/CSL/CISL computing resources when presenting results based on these simulations in either oral or written form. 

Project Details

  • Simulation Names:  
    • CMIP6/PMIP4 PlioMIP2 Tier 1 (midPliocene-eoi400 and piControl)
      • b.e12.B1850C5CN.f09_g16.preind.ccsm4 (CESM1-CAM4 preindustrial)
      • b.e12.B1850.f09_g16.PIMP4-pliomip2.ccsm4 (CESM1-CAM4 full PlioMIP2 BC)
      • b.e12.B1850C5CN.f09_g16.preind (CESM1.2-CAM5 preindustrial)
      • b.e12.B1850.f09_g16.PIMP4-pliomip2.modMed (CESM1.2-CAM5 full PlioMIP2 BC)
      • b.e21.B1850.f09_g17.CMIP6-piControl.001 (CESM2.1 preindustrial control)
      • b.e21.B1850.f09_g17.PMIP4-midPliocene-eoi400.001(CESM2.1 full plioMIP2 BC)
    • PlioMIP2 Tier 2  (All with CESM2.1)
      • b.e21.B1850.f09_g17.CMIP6-piControl.400 (CO2 = 400 ppm, preindustrial topography and land-sea mask, preindustrial vegetation distribution and ice sheets) 
      • (CO2 = 400 ppm, mid-Piacenzian topography and land-sea mask, preindustrial vegetation distribution and ice sheets) 
      • (CO2 = 280 ppm, mid-Piacenzian topography and land-sea mask, preindustrial vegetation distribution and ice sheets) 
  • Model Versions: CESM2.1 and CESM1.2 (either with CAM4 or CAM5, see descriptions above)
  • Resolution: 0.9x1.25_gx1v6 (CESM nominal 1o grid, with and without extended S. Ocean grid)
  • Years: varies
  • Ensemble Size: one each experiment
  • Time frequencies saved: monthly, daily (varies by component, CESM2 runs with additional 6-hourly for atm)
  • Machine: NWSC Cheyenne and Yellowstone

Data Acquisition

Tier 1 (multi-model cases):

The CESM1 CMIP6 Tier 1 PlioMIP2 simulations are available on the NWSC computing storage at /glade/collections/cdg/data/PlioMIP2/ and on NCAR’s Climate Data Gateway (CDG) at: 

The CESM2 PlioMIP2 Tier 1 simulation can be accessed through Globus in a Guest Collection here:

The CESM2 CMIP6 Tier 1 piControl simulation is available on the CDG here.

In addition, as Tier 1 CMIP6/PMIP4 experiments (midPliocene-eoi400 and piControl), the CESM2 simulations are available on the  WCRP CMIP6 Data Portal for CMIP6 formatted variables:  The DOI for the CMIP6 PlioMIP2 CESM2 simulation is

Tier 2 CESM2 Sensitivity experiments:

The CESM2 PlioMIP2 Tier 2 sensitivity simulations are available on NWSC /campaign storage at: 


For users who don’t have NWSC computing access, please contact: to get guest access through UConn HPC.



For CDG downloads (


Diagnostics for the PlioMIP2 baseline simulations can be found here: