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Latest CESM development code requires python3.6 or later


Bill Sacks
CSEG and Liaisons
Staff member
The latest CESM development code – starting with the cesm2_3_beta05 series – drops support for python2 and now requires python version 3.6 or later.

On cheyenne, you will need to load a python module before running create_newcase or any other CIME scripts. This can be done via module load python/3.7.9. See Environment modules | Computational and Information Systems Laboratory for instructions on how to save your module environment for future sessions so that you don't have to run this command every time.

If you maintain your own machine port, you may also need to update your config_machines.xml entry to load an appropriate python module, if python3 is not available by default on your system or the default version of python3 is older than version 3.6. See these recent CIME changes for an example of how to do this. In general, if you need to load a python module in order to run the cime scripts, then that same module load command should also appear in config_machines.xml.