@ecb80a47 Glacier bed rebound will indeed take decades to millennia, but sea level rise from dumping a subcontinent's-worth of meltwater into the oceans will be somewhat faster.
@0c1a9324 Yes. But I'd still like to know how much faster. It's not obvious how to work it out, either. I suppose I should try. The floating ice is floating; no change. The change in volume will come from glaciers moving off solid substrate (neglecting thermal expansion for now, and it's complicated anyway because the chemistry will affect it). The volume change is the simple bit. /cont