A serious problem is found in the diversion of agricultural resources to grow corn for ethanol. Over the last 5 years (2008 to 2012 inclusive), the U.S. has used an average of 4.566 billion bushels of corn per year to produce ethanol. At an average yield of 149 bushels per acre, the land used averages 30,621,689 acres per year, which is 12,392,158 ha.
That area of land is 86% of the land used to grow corn for livestock feed. But the livestock feed goes to produce animal-source foods. Although the land is being used inefficiently, it is still being used to grow food. When agricultural resources and actual food (maize) is used to make fuel ethanol, those food resources are utterly wasted.
If instead, we were to use that land to grow any type of food, there would be no loss to the world agricultural system. Taking land away from the production of cattle feed leaves us with the question as to how to feed the cattle. But taking land away from the production of fuel ethanol presents no such difficulty. It is fertile agricultural land that is available to feed the hungry, if only we had the will (or the funds).
Those 12,392,158 ha of land can grow 32,715,297 MT of fat from chufa at a moderate yield (11 t/ha) or 23,792,943 MT of fat at a low yield (8 t/ha). With either yield, the land is sufficient to grow enough dietary fat to exceed the unmet needs of the one billion hungry for dietary fat (22,400,000 MT). The largest part of the hunger problem can be solved by growing chufa instead of that fraction of the U.S. maize crop that is used solely for fuel ethanol.
Furthermore, the area of agricultural land used to grow maize and other crops for ethanol worldwide is much greater. It takes about 2.5 kg of maize to produce one liter of fuel ethanol. The billions of bushels of maize used by the U.S. for fuel ethanol production is about half of the world total. In 2011, the U.S. produced about 14.5 billion gallons of fuel ethanol (54.9 billion liters), from about 127.5 million MT (5.011 billion bushels) of maize. The world production of biofuel in 2011 was approximately 28.9 billion gallons (109.6 billion liters).
Not all biofuel is ethanol from maize. But land is used to produce the biofuel, and that land could have been used to produce food. In fact, it is typically food that is grown for production of fuel ethanol or other biofuels. Various vegetable oils can be converted into biofuel by esterification. Sugarcane can be converted into fuel ethanol, as is common in Brazil. While hundreds of millions of persons go hungry, we grow food and turn it into fuel.
Consider the possible macronutrient productivity of the U.S. agricultural land that is used to grow maize for ethanol. That land is almost sufficient to end world hunger by itself. About the same amount of biofuel is produced outside the U.S. as is produced in the U.S. So the land used for that fuel must be about the same, very approximately. Even if it were significantly less. It is apparent that just the land used to grow biofuel would be more than sufficient to grow enough food to end world hunger.