It feels like I should be able to read between the lines of https://docs.dask.org/en/latest/how-to/debug.html and https://docs.dask.org/en/latest/configuration.html to craft an environment variable name and value, but none of
DASK_DISTRIBUTED__LOGGING=DEBUG
DASK_LOGGING_DISTRIBUTED=DEBUG
DASK__LOGGING__DISTRIBUTED=DEBUG
DASK__LOGGING__DISTRIBUTED__SCHEDULER=DEBUG
nor the equivalents with 10 instead of DEBUG, nor some other combinations of order and underscore seem to do the trick.