Felix W. Landerer and colleagues at the Max Planck Institute for Meteorology in Hamburg say global warming will
slow down speed up Earth’s rotation by changing ocean bottom pressure, in the process shifting mass around:
We find a net transfer of mass from the Southern to the Northern Hemisphere, and a net movement of mass closer towards Earth’s axis of rotation. Thus, ocean warming and the ensuing mass redistribution change the length-of-day by ?0.12 ms within 200 years.
update, with an obvious correction.
Moving mass closer to the axis should speed rotation, not slow it. But melting polar ice sheets and raising global sea levels will move mass away from the poles (which are the axis, by definition).
Dangit! Am I going to have to reset all my clocks 3 weeks early again?
It’s the people whose birthdays falls on Feb 29th I feel sorry for.