Do food prices cause "food riots"?

The usually outstanding Chris Blattman has posted some spotty analysis of the recent journalistic coverage of food riots in Mozambique, which he finds "shallow and alarmist." I would have commented, but many have already done so, so rather than pile on I'll just articulate my own take here. Like commenter @Jonomist, I think his punchline that we should be more careful attributing causality is probably defensible, but some of his arguments are not.

Here’s what a closer look at your economics and political science can tell you.

Expect price volatility to fall over time. Globalization and growth should reduce price spikes in future. More countries are producing crops. Climate shocks in Argentina are not that tied to climate shocks in Russia or China, and so price volatility from supply shocks should be going down. Falling transport costs also mean that more substitutes are available, further reducing price volatility. So things should be getting better over time, not worse, especially if trade allows countries to diversify their diet. Envision a future of diminishing instability.

This is a dangerously superficial argument, reminiscent of arguments that a more integrated global financial system would mitigate systemic risk - remember how that turned out? It's what a textbook analysis would say, but lacks grounding in the realities of these markets.

• Empirical data (most recently the price spikes of 2008 and now 2010) don't bear this out, at least in retrospect to date.


• Many agricultural stakeholders - including private companies both producing and buying food, as well as multi-laterals such as the FAO and the World Bank - are deeply concerned with price volatility in the future. (My own view is that we can't yet tell if average volatility will increase to a higher permanent plateau, but most players believe this is much more likely than the opposite.)


• Growth in both population and income is driving strong growth in agricultural demand that is unlikely to abate soon, and pushing the world toward the edge of its current supply capacity. Production can grow too (Ehrlich and Malthus were wrong) through increasing yields through research and bringing more land under cultivation, but the former is longer-term and the latter runs into seriously diminishing marginal returns. My personal belief is that we will be able to feed 9 billion people a more modern diet by 2050, but there will be bumps along the way, and any time demand nears supply capacity, the potential for price volatility increases significantly.


• Climate may become more unstable as climate change progresses, and climate change could also adversely affect baseline agricultural productivity, as Michael Roberts' excellent paper has shown and the market seems to believe.


• As several commenters noted, national policies play a substantial role in agricultural prices (notice how the wheat market responded to the Russian wheat export ban), and this intervention seems unlikely to diminish (especially in light of the above factors) - if anything it is likely to exacerbate any increases in underlying volatility caused by long-term demand growth and short-term supply shocks.

A few smaller nits:

Look to local policy, not global markets, for the real instability. Bread prices climbed 30% in Maputo, apparently due to Russian wildfires. But global wheat prices have only risen 5%. Why the disproportionate effect? I wish I knew, except I haven’t a single report from the ground that points out the disparity, let alone one that searches for an answer.

Yes, global wheat prices have risen 5% "during August" - and more than 50% since June, as commenter Bernhard Brummer points out. Some of the blame goes to the NYT writer for not picking a better baseline, but it's not a hard thing to double-check.

Chris: For riots, look to poor policing, not poverty.
@Jonomist: Are fires caused by insufficient fire marshaling?

Exactly.

Chris' track record is too strong for him to need to redeem himself, but he does so anyway (I'm not sure if intentionally) through his next post on the quality of his commenters (who came through rapidly here).