Studies of U.S. biofuels expansion have more often focused on assessing the price
impacts of biofuels policies rather than simply their expansion. Abbott, Hurt et al. in
2008 estimated that such policies were responsible for about one-quarter of the increase
in global corn prices, the remainder attributable mainly to higher oil prices (Abbott, Hurt
et al. 2008). Their follow up study from 2011 suggested that two major drivers of food
prices in the 2010-11 spike were U.S. biofuels (overwhelmingly corn ethanol) and rising
Chinese soybean demand (Abbott, Hurt et al. 2011).