Oh, I forgot to mention this, which appears on teh same issue.
Water for farming: Running dry; The world has a water shortage, not a food
shortage. http://www.economist.com/world/international/displaystory.cfm?story_id=12260907&CFID=22457458&CFTOKEN=62430820
My comment:
(1) there is no need to read the article. Just look at the chart.
Oversimplified, yes. But informative.
(2) What is amazing to me is Manchuria and part of Tibet have plenty of
water. Perhaps due to overpopulation, northern China
