These articles give a partial answer to that question. While drought and food prices don't cause revolution and geopolitical conflict by themselves, they are increasingly seen as an important factor:
If you want to predict where political instability, revolution, coups d’etat, or interstate warfare will occur, the best factor to keep an eye on is not GDP, the human development index, or energy prices.
“If I were to pick a single indicator—economic, political, social—that I think will tell us more than any other, it would be the price of grain,” says Lester Brown, president of the Earth Policy Institute, who has been writing about the politics and economics of food since the 1950s.
Food, of course, is never the sole driver of instability or uprising. Corruption, a lack of democracy, ethnic tension—these better known factors may be critical—but food is often the difference between an unhappy but quiescent population and one in revolt.
Take Venezuela, where a toxic combination of gas subsidies, currency controls, and hoarding have led to chronic food shortages—a major factor motivating the anti-government protests that have wracked the country since the beginning of this year.
And perhaps Dmitry Orlov should look at grain in addition to oil:
The Arab Spring may become the textbook example of the geopolitics of food prices—the food riots and subsequent revolutions transfixed the world. But shifts in food price may be responsible for an even more profound reordering of global power. Food may explain why everything changed during the 1980s.Food riots and revolution: Grain prices predict political instability (Slate)
After a price shock in the late 1970s, food prices underwent a slump during the early and mid-1980s. A confluence of factors included slowing economic growth; the spread of the “green revolution,” which improved the efficiency of agriculture in developing countries; and the falling price of oil.
This slump played a role in many of the larger geopolitical trends of the era, according to Argentinian economist Eugenio Diaz-Bonilla. The Soviet Union, which was a net exporter of commodities, was hit hard economically, and by the end of the decade was near collapse. Growth was sluggish throughout the decade in Latin America, where most economies are based on agriculture. Dictatorships were overthrown in Ecuador, Argentina, Brazil, Uruguay, and Chile. African countries entered a period of economic stagnation and civil strife that the continent only recently started to recover from. The emerging tigers of East Asia, meanwhile, such as China and South Korea, benefited from low prices on the food they import.
In the 1990s, food prices began to rise and have continued increasing ever since, with the exception of a brief blip during the global economic crisis in the late 2000s. Overall, the food price index as measured by the U.N.’s Food and Agriculture Organization is twice what it was in 1991. There’s little to suggest they’re going to fall any time soon.
Francesco Femia and Caitlin Werrell are co-founders of the D.C.-based Center for Climate and Security, a think tank focused on the interactions between climate change and security issues. In recent years, they've published a number of reports looking at the environmental roots of both the Arab Spring and the ongoing civil war in Syria.
Brad Plumer: You also published a collection of papers looking at environmental and climate-related factors that may have contributed to the 2011 revolts across the Arab world. What were the big climate drivers there?
Francesco Femia: We looked at a number of different dynamics. Troy Sternberg, Sarah Johnstone and Jeffrey Mazo looked at the impacts of climate change in Ukraine and Russia and how droughts in those parts of the world in 2010 may have contributed to a wheat shortage. That, in turn, led China to purchase a lot of wheat on the global food market [which led to spikes in the price of food worldwide].
Again, they don't claim that the price spikes caused the revolution in Egypt or Tunisia. But they do look at how those prices spikes led to parallel bread protests in Egypt in particular. The point here is that the proximate cause of the protests that led to [Egyptian President Hosni] Mubarak's downfall may have been the response to the earlier Tunisian revolt. But the broader appeal of that movement in rural areas may have been partly due to the fact that bread prices were high. The Egyptian government tried to use subsidies to keep the price of bread down, but that didn't affect rural areas.
So food prices may have played a role in broadening the appeal of the protests, but we would say it was one factor.
Caitlin Werrell: A lot of the research we've done basically concludes by calling for more research, so that we can see how these correlations can be fleshed out better. Sternberg calls it the "globalization of hazards." A drought or wildfire that was exacerbated by climate change can have drastic impact thousands of miles away.
FF: And we should note that the top nine countries in terms of wheat imports per capita are in the Middle East and North Africa. So anything that affects prices could affect these countries. But more research needs to be done to disentangle climate as a factor.
BP: So let's talk about the future. There are all sorts of predictions that global warming will lead to drought or heat waves that hurt agriculture. And it's a bit tricky because many models still have trouble pinning down precise regional impacts. But which of these things should security analysts pay attention to?Drought helped cause Syria’s war. Will climate change bring more like it? (Washington Post)
CW: A lot of the way we approach climate change as a risk is to say it’s a "threat multiplier." The way it combines with water or food can take an existing conflict and make it worse, or take a stable situation and make it worse.
One example we find is if you look at Egypt, at the Nile Delta, the projections from the Intergovernmental Panel on Climate Change say that they'll see at least 59 cm of sea-level rise by 2100. Not only does that create a problem with flooding in urban areas, but there's also the problem of saltwater intrusion in fresh aquifers. About 34 percent of agricultural production occurs in that area. A lot of focus in Egypt right now is how to get a more stable government, but if you want to look at how to build a stable government, you'll need to be looking at issues like sea-level rise.
FF: One area where the intelligence community has taken notice is water. There was a recent assessment by the National Intelligence Council that looked out 30 years and mentioned climate change quite often. In some places you get too much water, in others too little, you get unpredictable flows as monsoon seasons and drought seasons change. So that's something the intelligence community will have to take into account when thinking about fragile states.
There was a recent report from the International Food Policy Research Institute for Syria projecting that at current rates of greenhouse gas emissions, yields of rain-fed crops may decline between 29 percent to 57 percent between now and 2050. That’s something we'll have to take into account when thinking about fragile states.