More food price volatility drivers

Upon further reflection on Chris Blattman's rare dud, here are a few more (slightly overlapping) potential drivers of food price volatility in the future. Please note that I'm not saying these will definitely cause higher food price volatility in the future, only that it is very easy to believe that they might.

• Biofuels and bioenergy: An additional source of demand growth - potentially very large - that could keep demand at the very edge of supply capacity.


• Stronger links to energy prices: Energy prices have always been linked to agricultural input costs since the most widely used fertilizer (nitrogen) is generally made from natural gas. More recently ethanol has become at times the marginal buyer of corn (Bruce Babcock at CARD did some nice research demonstrating that ethanol was the marginal buyer from late 2007 to mid 2008; I couldn't find a link to the paper, but all you need to do is look at the high correlation between actual corn prices and break-even prices for ethanol production). If this continues - and it may well, particularly when oil prices are high - then volatility in oil prices will be transmitted to food prices more than in the past.


• Speculation: That old bugbear; I personally am more skeptical about this one, as longtime readers will know, but the former head of IFPRI isn't, and objectively I'm no more likely to be right than he is.
  

Update: Michael Roberts responds and reprimands:

Here Chris seems to talking as much about climate science as economics or politics. He has also stepped onto a pet peeve of mine, common among some economists, which is ascribing personal views as truisms stemming from the branch of social sciences in which one specializes. It's not quite as bad as Steven Levitt pontificating about global cooling, but it reeks of that kind of professional arrogance. If you're an academic and are going to start asserting scientific truisms you need to be more specific about the underlying science.

He also points out a few factors not yet on my list, which I'll paraphrase here:

• Globalization is not irreversible: Think about how surprisingly globalized the world became during 1870-1914, only to regress drastically following World War I and the Great Depression.


• Shifts in comparative advantage due to climate change, which Michael is "convinced" of:
  

  That is, [climate change is] going to shift where things are grown. A lot. It's also likely to change global quantities, but that's hard thing to put a finger on (i.e., model convincingly). With that much change going on, we should worry at least a little bit, and probably a whole lot, about how the kind of turmoil these changes will cause. Loss of comparative advantage is just the kind of thing that brings about bad policy response.

• Uncertainty itself can exacerbate market volatility, and uncertainty about the future is high, not just about long-term commodity prices, but also about the direction of the world economy and shifts in agricultural production due to climate change.