Climate Variability & Change
Working Group CVCWG

CESM2 SSP2-4.5 Ensemble

This is a 16 member ensemble of simulations with CESM2 under the SSP2-4.5 forcing scenario from 2015 to 2100. These simulations can be compared with the CESM2 large ensemble and provide the opportunity to compare and contrast climate change under a lower forcing scenario. One difference from the official CMIP6 SSP2-4.5 forcing is that slightly modified biomass burning emissions are used at the beginning of the simulation. As will be discussed in a forthcoming article documenting the CESM2 large ensemble (Rogers et al, in prep), the second 50 members of the CESM2 large ensemble use smoothed biomass burning emissions over the GFED era of the late 20th/early 21st centuries. While the GFED emissions were not prescribed in the SSP scenario, there is a minor effect of the smoothing into the first years of the SSP scenario and these simulations have been branched from historical simulations that used the smoothed biomass burning emissions. As such, this medium ensemble is complementary to the second 50 member of the CESM2 large ensemble. Specific information of which member is initialized from which historical member of the CESM2 large ensemble is provided below.

We kindly ask that you acknowledge the CVCWG when presenting results based on the CESM2 SSP245 Ensemble in either oral and written form.

Project Details

  • Simulation Names:
    • b.e21.BSSP245smbb.f09_g17.001.0XX, XX = 01-16
  • Model Version: CESM2.1.2 Codebase | Documentation
  • Resolution: 0.9x1.25_gx1v6 (CESM nominal 1o grid)
  • Years: 2015-2100
  • Ensemble Size: 16 members
  • Time Frequencies Saved: Monthly, Daily
  • Machine: NCAR:Cheyenne
  • Compsets: BSSP245smbb
  • Initial Conditions: Started from the end of:
    b.e21.BHISTsmbb.f09_g17.LE2-1231.011 (run 001)
    b.e21.BHISTsmbb.f09_g17.LE2-1231.012 (run 002)
    b.e21.BHISTsmbb.f09_g17.LE2-1231.013 (run 003)
    b.e21.BHISTsmbb.f09_g17.LE2-1231.014 (run 004)
    b.e21.BHISTsmbb.f09_g17.LE2-1231.015 (run 005)
    b.e21.BHISTsmbb.f09_g17.LE2-1231.016 (run 006)
    b.e21.BHISTsmbb.f09_g17.LE2-1231.017 (run 007)
    b.e21.BHISTsmbb.f09_g17.LE2-1231.018 (run 008)
    b.e21.BHISTsmbb.f09_g17.LE2-1251.012 (run 009)
    b.e21.BHISTsmbb.f09_g17.LE2-1251.013 (run 010)
    b.e21.BHISTsmbb.f09_g17.LE2-1251.014 (run 011)
    b.e21.BHISTsmbb.f09_g17.LE2-1251.015 (run 012)
    b.e21.BHISTsmbb.f09_g17.LE2-1251.016 (run 013)
    b.e21.BHISTsmbb.f09_g17.LE2-1251.017 (run 014)
    b.e21.BHISTsmbb.f09_g17.LE2-1251.018 (run 015)
    b.e21.BHISTsmbb.f09_g17.LE2-1251.011 (run 016)
  • Additional Notes: CMIP6 time-varying external, natural and anthropogenic forcings from SSP2-4.5 were specified in this ensemble, with the exception that smoothed biomass burning emissions were specified in place of the CMIP6 SSP2-4.5 biomass burning estimates.

Data Acquisition

The data is available from NCAR/CISL's campaign store accessible via the NCAR machine casper at:
If you do not have access to the CISL campaign store or NCAR's casper machine you can contact the CVCWG liaisons for assistance.