Is it possible that the LOD correlation to multidecadal global temperature variations is just an example of a forcing response to an ocean basin's sloshing behavior?
Changes in LOD are angular momentum changes and those get directly translated to forcing inputs to the precarious thermocline stability. The ~4 year lag between forcing and response may be explained by the thermal mass in the system.
Once the SOI Model is integrated into CSALT, the only unknowns left to natural variability are LOD and volcanic impact. Since multi-year LOD is slowly varying, that may be relatively easy to forecast a few years in advance, which only leaves volcanoes as an unknown.