In 2015, the U.S. used about 5 billion bushels of corn to produce over 13 billion gallons of ethanol fuel.
The grain required to fill a 25-gallon gas tank with ethanol just once can feed one person for a year, so the amount of corn used to make that 13 billion gallons of ethanol will not feed the almost 500 million people that it might have served. That is more than the population of North America.
Seventy percent of all corn imports worldwide come from the U.S.
Food price spikes affect the poor immediately. In the run up to 2007, the global price of corn doubled as a result of an explosion in ethanol production in the U.S. coupled with the Great Recession. In eastern Africa alone, 400,000 died as a result according to the World Health Organization.
Competition in the marketplace is troublesome, sometimes. Because corn is the most common animal feed and has many other uses in the food industry, the price of milk, cheese, eggs, meat, corn-based sweeteners and cereals increased as well. World grain reserves dwindled to less than two months, the lowest level in over 30 years.
Globalization is more complicated than we expected; it's not going to be easy to avoid doing harm.