One of the extra impacts from sea level rise is that the spin of the Earth will slow down. The melting of polar ice sheets is already moving weight from the poles into the oceans, which generally are not at the poles.
We’re losing about a gigatonne of ice per day, roughly a cubic kilometre (give or take quite a bit). This is a reasonable chunk of ice now melted and heading towards the equator. Still, the Earth weighs about five million billion gigatonnes.
The overall effect depends upon what ice melts, and where the water ends up in the oceans, coz the oceans are not that flat, overall. So the numbers are pretty vague right now. A metre of sea level rise might lengthen each day by maybe 0.01 seconds. For comparison, the eearthquake that caused the Asian tsunami to lengthen by maybe 0.000002 seconds. So 0.01 seconds is huge, as these things go.
(Also, 1 metre sea level rise means approximately 100 million people homeless, give or take err… quite a lot.)