The answers to this question say that the sea level will rise 66m if all the polar ice, etc, melts.

How long will this take?

Transporting incredible amounts of heat energy to the poles and injecting it into the ice, a good insulator, so that it melts must be very, very slow. The Netherlands, London, and all the rest will be long gone for other reasons, I imagine, long before it could be completed.

We need some numbers.

How much ice is there?

( Antartica contains 26.5 million cubic km of ice

http://en.wikipedia.org/wiki/Antarctic_ice_sheet

So: 2 * 10 ** 14 kg )

How much heat energy is needed to melt a unit of ice?

( 333 kJ/kg.

http://www.ask.com/question/how-many-joules-of-heat-are-required-to-melt-40-kg-of-ice-at-0-degress-c )

So we need 6 * 10 ** 16 kJ

I reckon that this is the amount of energy striking the entire Earth from the sun every two minutes. However, getting this energy from the top of the atmosphere into the ice sheet will take a little longer.

How good an insulator is ice?

( 2 watts per meter per Kelvin http://en.wikipedia.org/wiki/List_of_thermal_conductivities )

Antartic ice is about 2km thick. Let's replace this with a 1km blanket of ice equivalent insulator. In this case, if the air temperature rises 8 degrees celsius, then energy arrives at the bottom of the blanket at the rate of ... X

Antartica is 14 * 10 ** 6 km2 so we are able to deliver energy at Y watts

6 * 10 ** 16 / Y = Z seconds