Last week I served on a panel for the RTEC and gave my usual spiel about ethanol and food prices.
In a nutshell:
1) Both supply and demand of staple grains are highly inelasitic. This means it doesn't take much of a shift in supply or demand to cause a big change in price.
2) The U.S. is hugely important in world grain markets. With the largest share of world production and a much larger share of world exports, we drive international prices for staple grains.
3) Ethanol uses about 1/3 of the U.S. corn crop, or about 5 percent of the calories produced, worldwide, of corn soybeans, wheat and rice--the key grains that feed the world. That's even with a bigger corn crop (and smaller soybean crop) that has been brought about by ethanol subsidies and mandates.
4) When prices go up, we in rich countries don't eat much less, since commodities are a trivial share of our food expenditures. Those consuming less are most plausibly the world's poorest. If not, who do you think is eating less due to the huge diversion from ethanol?
5) Yes, there are other and possibly larger factors affecting food prices: growth in China and other parts of the world, particularly growth in demand for meat, and bad weather. These factors accentuate the effects of ethanol; they don't diminish it. A big problem with all this stuff coming online at the same time is that it has drawn down inventories, making markets far more susceptible to other shocks.
I was challenged by the usual armchair reasoning that doesn't hold up under inspection. Yes, some of the grain used in ethanol production goes back to farmers in the form of distillers grains. But it cannot be used for all animals. It's 1/3 the calories, maybe less. The wet stuff is economical but very expensive to transport.
In the real world there are tradeoffs. You can't have your cake and eat it too.
One anecdote I wish I mentioned but didn't: In October, the USDA revised its crop forecast for corn downward by about 5% from the September forecast. This is a nice thing to look at because it provides something of a natural experiment--a large, clear, measurable unexpected shock to the market. This supply shock caused prices to go up nearly 10% on the same day.
Consider how large this small adjustment on quantity had on price. Now consider that this production shock was likely due to late season weather, a temporary phenomenon. Now consider that ethanol is a permanent shock that is about six times the size on an annual basis.
If you say you don't think ethanol is affecting prices for staple grains and soybeans, you are a fool or a knave looking to mislead.