This error is written from ice_itd.F when the ice model is checking that initial and final values of a conserved field are equal to within a small value. The output looks like:
Conservation error: vice, add_new_ice 11 : 14 185 Initial value = 1362442.600400560 Final value = 1362442.600400561 Difference = 2.328306436538696D-10 (shr_sys_abort) ERROR: ice: Conservation error (shr_sys_abort) WARNING: calling shr_mpi_abort() and stopping (shr_mpi_abort):ice: Conservation error 0
Non-conservation can ocur if the ice model is receiving very bad forcing, and is not able to deal with it. This has occurred after a CFL violation in the ocean. The timestep in the ocean may be decreased to get around the problem.