
Thomas S. answered 08/07/20
MS in Geology and a BS in Physics with a Minor in Geology
So you set this up like an equation with what you know and the key is to solve this you must assume the ocean area doesn't change, but first lets just start by defining some things.
So volume is base x width x height, so essentially volume of oceans bowo= 361.9 mil km2 and we know the volume of the current ocean is 361.9 mil km2 x hocean
I'll also write it as bowoho= 361.9 mil km2 x ho
We know the new sea level is ho+hrise and assuming sea area doesn't change we can make the equation.
bowo(ho+hrise)=361.9 mil km2 x ho + 26.5 mil km3
or for just ease of writing
bowo(ho+hrise)= bowoho + 26.5 mil km3
then you solve for hrise
bowoho+bowohrise= bowoho + 26.5 mil km3
bowohrise=bowoho - bowoho + 26.5 mil km3
bowohrise=26.5 mil km3
hrise=26.5 mil km3/bowo
hrise=26.5 mil km3/361.9 mil km2 the answer should be in km so here we can check that the units of the answer will be in km since km3/km2 = km
hrise=0.07322 km
hrise=0.07322 km x 1000m/km = 73.2m
relative sea level rise from all the ice sheets melting would be about 73.2m