@b541bfe5 
Even funnier when it's about definition of multiplication/divsion by two... 

 @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 

 @0c1a9324 
I am not clear about the timescale.  Rebound of the glacier bed doesn't seem likely to occur on a ten-year timescale, does it?  Puzzled.