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 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 is discussed in the CESM2 Large Ensemble reference paper (Rodgers et. al. 2021), 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.

For more information about this ensemble visit the CESM CVCWG CESM2 SSP2-4.5 Ensemble website.