Global warming is expected to result in sea level rising. Extra water is added by melting ice and increased temperature causes expansion of water. Thermal expansion alone will cause upto 0.7 m rise in sea level by 2100 (IPCC 2007). If all of arctic ice melts then sea levels could rise by 7 metres and far more if antarctic ice melts.
It is interesting to see what areas of the world will be affected by sea levels rising. Low lying areas - of course. The effect can be seen on the maps by clicking on the following links: The links are interactive and you can choose your own values and area.
http://flood.firetree.net/?ll=45.5833,14.6777&z=13&m=0 Europe now
http://flood.firetree.net/?ll=53.3112,4.2407&z=10&m=1 Europe with 1 m rise in sea level
http://flood.firetree.net/?ll=53.0280,4.6472&z=10&m=5 Europe with 5 metres rise is sea level
Notice the vast areas of the Netherland and Denmark being affected even with a 1 m rise. 5 metres rise in sea level will flood a lot of Essex and Yorkshire.