Some basic math re melting of the ice caps and the potential subsequent rise in sea level.
The Antarctic ice sheet contains about 85%-90% of the ice on the planet Earth.
The land area of Antarctica is ~5.48 million square miles.
The average ice thickness (from 0 ft in some coastal areas to the maximum inland) of the ice sheet is 1.4 miles (that's right - nearly 7,400 ft thick).
The amount of ocean area on the surface of the earth (as in Thumpalumpacus's post above) is ~140,000,000 square miles.
If we ignore the north pole Arctic ice sheet (it is mostly floating) and the other mountainous glaciers/ice sheets on land (Greenland, the Alps, the Himalayas, etc) then we can multiply the land area of Antarctica by the average ice thickness of the Antarctic ice sheet and figure out how much additional water the oceans will have to accommodate (at the most, assuming nothing else changes):
5,480,000 x 1.4
= 7,672,000 cubic miles of ice melt.
If we then divide the increase in volume of liquid by the total area of the oceans:
7,672,000
÷ 140,000,000 = 0.0548 cubic miles (that's 8,066,447,770 cubic feet) of water per square mile of ocean surface.
If we then divide the cubic foot volume of water increase by the area of a square mile in feet:
8,066,447,770 ÷ 27,878,400
= 290 feet of sea level rise.
How many areas along the coasts, and areas inland if accessible by waterways (current or past), will be covered by such an increase in sea level?
The calculated rise in sea level would be offset to a degree by whatever land areas ended up being covered by water, since the effective land area would decrease by some amount and the effective ocean area would increase by a similar amount. I do not have the data to calculate the amounts involved.
Even if we assume that 50% of the ice melt becomes a continuous weather event - ie evaporation and condensation to rain - that would still be a sea level increase of 145 feet. Ask the same question as above as to the effect on low lying coastal and inland areas.
But now you have an enormous increase in water vapor in the atmosphere at any point in time, acting as a greenhouse gas, and increasing the ambient temperatures even more. Plus, you also now have enormous rainfalls all over the Earth. If you spread the 145 feet of ice melt trapped in the continuous weather event evenly over the surface of the earth, that would result in rainfalls of:
If the total surface area of the Earth
= ~1,966,628,896 square miles, and
The total ice melt tied up in the continuous weather event is 1/2 of the total ice melt of 7,672,000 cubic miles
= 3,836,000 cubic miles, then
3,836,000
÷ 1,966,628,896
= 0.00195 cubic miles of rain per square mile of the Earth's surface per day on average, or a little over 10 ft of rain per square foot of the Earths's surface per day, or a little over 5" per hour.
Obviously, the rain would not be constant all over the Earth all the time, but that just means that if the rain was only falling on 1/2 the Earth's surface at any point in time it would be double the amount per hour or day on the other half of the planet and/or at other points in time.
And this is if every thing else remains the same (it would not).
Incidentally, the highest total yearly rainfall in today's world is about 400 inches, so averaged out over 365 days that is only about 1.1 inch per day, while the record rainfall (anywhere) is about 17 inches in one hour.
Talk about erosion by ocean waves and rain. Yikes!
Bleh! Hopefully I did the math right.