By: Rana Foroohar

None of the factors that drove the global food crisis in 2008 have gone away. Agricultural production is still tapped out, trade barriers are high, and demand, especially from emerging markets, is growing. Now there's an increasing worry over the availability of key inputs like fertilizer. You probably didn't know it, but the world is running out of phosphate fertilizer. All agricultural crops need phosphates, which are a key ingredient in the industrial fertilizers that have helped raise global yields in recent decades. But supplies of phosphate rock--90 percent of which are found in the U.S., Jordan, South Africa, Morocco, and China--are shrinking. Demand from China in particular is growing, driving the rate of phosphate extraction up from its usual 2 percent a year to some 7 percent last year. Academics at the University of Technology in Sydney believe "peak phosphate" supply could come by 2030. Already, the U.S. has been forced to import to meet its needs, and while reserves data are sketchy, there are some signs China may be hoarding phosphate. All this worries food experts, who note food prices are up some 10 percent this year, and small farmers (the world's majority) are struggling to get loans to increase production because of the fallout from the credit crunch. At a U.N. food-security conference in Rome two weeks ago, ­Secretary-­General Ban Ki-moon called on rich nations to up R&D spending in agriculture to encourage the development of new kinds of high-yield crops, artificial phosphates, and other farm ­innovations.