National Academy of Sciences Examines Climate Change Impact on Ag Water
A warmer world is expected to have severe consequences for global agriculture and food supply, reducing yields of major crops even as population and demand increases. Now, a new analysis combining climate, agricultural, and hydrological models finds that shortages of freshwater used for irrigation could double the detrimental effects of climate change on agriculture.
Given the present trajectory of greenhouse gas emissions, agricultural models estimate that climate change will directly reduce food production from maize, soybeans, wheat and rice by as much as 43 percent by the end of the 21st century. But hydrological models looking at the effect of warming climate on freshwater supplies project further agricultural losses, due to the reversion of 20 to 60 million hectares of currently irrigated fields back to rain-fed crops.
http://www.sciencedaily.com/releases/2013/12/131216154330.htm