 use_c13        = .true.
 use_c14        = .true.

 ! BUG(wjs, 2018-10-25, ESCOMP/ctsm#67) There is a bug that causes incorrect values for C
 ! isotopes if running init_interp from a case without C isotopes to a case with C
 ! isotopes (https://github.com/ESCOMP/ctsm/issues/67). Normally, an error-check prevents
 ! you from doing this interpolation (until we have fixed that bug). However, we
 ! sometimes want to bypass this error-check in system tests. This namelist flag bypasses
 ! this error-check.
 for_testing_allow_interp_non_ciso_to_ciso = .true.
