The Great Tortilla Crisis

Krugman-Wells-Grady

“Thousands in Mexico City protest rising food prices.” So read the headline in the New York Times on February 1, 2007. Specifically, the demonstrators were protesting a sharp rise in the price of tortillas, a staple food of Mexico’s poor, which had gone from 25 cents a pound to between 35 and 45 cents a pound in just a few months. Why were tortilla prices soaring? It was a classic example of what happens to equilibrium prices when supply falls. Tortillas are made from corn; much of Mexico’s corn is imported from the United States, with the price of corn in both countries basically set in the U.S. corn market. And U.S. corn prices were rising rapidly thanks to surging demand in a new market: the market for ethanol. Ethanol’s big break came with the Energy Policy Act of 2005, which mandated the use of a large quantity of “renewable” fuels starting in 2006, and rising steadily thereafter. In practice, that meant increased use of ethanol. Ethanol producers rushed to build new production facilities and quickly began buying lots of corn. The result was a rightward shift of the demand curve for corn, leading to a sharp rise in the price of corn. And since corn is an input in the production of tortillas, a sharp rise in the price of corn led to a fall in the supply of tortillas and higher prices for tortilla consumers. The increase in the price of corn was good news in Iowa, where farmers began planting more corn than ever before. But it was bad news for Mexican consumers, who found themselves paying more for their tortillas. ▲