This might be a good time to start stockpiling Slim Jims. From The Guardian:
Leading water scientists have issued one of the sternest warnings yet about global food supplies, saying that the world's population may have to switch almost completely to a vegetarian diet over the next 40 years to avoid catastrophic shortages.
Humans derive about 20 percent of their protein from animal-based products now, but this may need to drop to just 5 percent to feed the extra 2 billion people expected to be alive by 2050, according to research by some of the world's leading water scientists.
"There will not be enough water available on current croplands to produce food for the expected 9 billion population in 2050 if we follow current trends and changes towards diets common in western nations," the report by Malik Falkenmark and colleagues at the Stockholm International Water Institute (SIWI) said.