Here's a superb Flash map produced by the UK Met Office (see more info and the full size interactive view) which shows the likely results for different regions if the world's average temperature rises by just 4° C.
The map was presented to OECD Secretary-General Angel Gurría by Dominic Martin, British Ambassador to the OECD, ahead of UN climate change talks in Copenhagen in December.
Source: OECD press release 22 October 2009, which has some frightening figures:
"OECD analysis suggests that unless action is taken, global greenhouse gas emissions will rise by about 70% between now and 2050, and by 2100 there could be 4-6 C global mean increase in temperatures above pre-industrial levels.
The map shows that, for instance, as the Himalayan glaciers melt, 23% of the population of China could be deprived of the vital dry season glacial melt water by 2050.
It explains too that an estimated mean sea-level rise of 53 cm by 2075 would result in floods affecting an additional 150 million people, with Asia being particularly badly hit."