Can anyone explain this conundrum to me please?
Fill a pint glass with a mixture of ice-cubes and water to the very top. Leave it to stand until the ice cubes melt and the water level falls. Ergo, water expands when it turns to ice and vice-versa, it contracts when it melts.
Using this principle, why would the melting of the polar ice-cap cause sea levels to rise? Surely they would fall as the ice melts and contracts…
I believe it may have something to do with all the water frozen over landmasses. Antarctica comes to mind… think how much ice is stored there.
I’m afraid i don’t have an answer for you (although ryoushi’s comment seems very sensible), but i did just pop in to say that i pondered over this for ages and no one i knew was able to give me a sensible answer. But now i feel at rest.
I’ll find out how much ice is in Antarctica if you like, it’ll make disproving me easier. 
Thanks ryoushi. I take your point about the ice on the land masses. However, which would melt first or quickest… the ice in/on the sea or that on the land?
Also, if temperatures were to rise in general, so would evaporation and so presumably, more of the water would be in the sky as clouds.
(How on earth would you go about establishing the amount of ice on Antarctica?)
You would do a search on the net and quickly arrive at a statement like this: