[unavoidable]

Potentially related is the centrifugal effect - the Earth bulges at the equator slightly because of spin. Logically, melted ice would tend to cause water to "rise" more at the equators (further from the ice caps) than near the poles.

[droopyEyelids]

...and that would slow the rotation of the earth.

I'd love to see a calculation of how much ice would have to melt for us to add another leap second.

Or to back it up, how would timekeeping bodies deal with that?

Would we actually remove a second because there would technically be less "time" (measured in days, meaning axial revolutions of the Earth) per year?

[Johnythree]

It's been done. I can't find the reference, but apparently the extreme accuracy of atomic clocks has proven that the mass of water moving from the poles to the equator has slowed the earth's rotation as predicted.

[leephillips]

There's a reference and some discussion at http://arstechnica.com/science/2016/04/the-leap-second-becau...