Nice map here from the Guardian showing this issue. See here. This map shows the change in run-off worked out from records worldwide between 1948 and 2004, with blue shades indicating more water and reddish colors less water. This really is climate change "in your face". look at the UKs plus figure and remember the flooding problems we have had in our country in recent years. Some of these have been written on this blog. Do a quick search at the top on flooding. As this article says though the worst areas affected are in Africa and water may be the cause of the next war.