A peer-reviewed study by Elizabeth Ainsworth of the University of Illinois called “Rice Production in a Changing Climate” warns that increased temperatures and ground-level ozone concentrations threaten to drastically reduce rice yields around the world. New strains of rice must be bred immediately in response to the threat of a worldwide rice shortage.  Dr. Ainsworth said, “In places where the demand for food is already too great, things are going to get worse.” 

 http://environment.newscientist.com/channel/earth/climate-change/dn13517-major-food-source-threatened-by-climate-change.html