Results of experiment
To those who replied to my comment about the sea level actually dropping - thanks for that. I did the experiment with ice cubes and water last night when I got home from work and you're absolutely right: the water level in the glass does not change because of ice melt.
I performed the experiment with two glasses: one (A) with water + ice cubes, the other (B) with just water as a control. In the time it took for the ice to melt (48 min), the water level in glass A decreased by 0.16 mm, while the water level in glass B decreased by 0.18 mm, measured with a digital 0.01mm resolution vernier gauge.
Conclusions: This discrepancy could be either due to evaporation, since the water in glass B was warmer and therefore would have evaporated slightly faster, or it could also (more likely) be due to errors in measurement. I have no reason to believe the ice melting was the cause of the 0.02 mm discrepancy, since given the volume of ice in glass A, and the volume of ice compared to that of the equivalent mass of water, if this volume difference were a cause, the discrepancy would have been considerably more than 0.02 mm.
Either way, I believe I have just demonstrated, by scientific method, that the ice caps melting will not cause any change in sea level. Note that this does not take into account ice on land (glaciers, mountaintops, Antarctica etc.) If this ice melts, then it will run into the sea. However, given the volume of the sea compared to land, coupled with the small land area actually covered by ice, it is highly unlikely that this would cause a change in sea level of more than a few centimetres at most. As I'm not a scientist, I could not give an exact figure on this, but I certainly don't believe the hype about coastal cities being drowned by rising sea levels.
So there you go. Global flooding as a result of global warming is bullshit.