In many discussions of climate change impacts in agriculture, the large magnitudes of expected impacts toward the end of the century are used to emphasize that most of the risks are to future generations. However, this perspective misses the important fact that demand growth for food is expected to be much slower after 2050 than before it, and that the next two decades represent the bulk of growth before 2050. Thus, impacts of smaller magnitude in the near-term can be as or more consequential for food prices or food security as larger magnitude impacts in the future. Here we estimate the risks that climate trends over the next 10 or 20 years could have large impacts on global yields of wheat and maize, with a focus on scenarios that would cut the expected rates of yield gains in half. We find that because of global warming, the chance of climate trends over a 20 year period causing a 10% yield loss has increased from a less than 1 in 200 chance arising from internal climate variability alone, to a 1 in 10 chance for maize and 1 in 20 chance for wheat. Estimated risks for maize are higher because of a greater geographic concentration than wheat, as well as a slightly more negative aggregate temperature sensitivity. Global warming has also greatly increased the chance of climate trends large enough to halve yield trends over a 10 year period, with a roughly 1 in 4 chance for maize and 1 in 6 chance for wheat. Estimated risks are slightly larger when using climate projections from a large ensemble of a single climate model that more fully explores internal climate variability, than a multi-model ensemble that more fully explores model uncertainty. Although scenarios of climate impacts large enough to halve yield growth rates are still fairly unlikely, they may warrant consideration by institutions potentially affected by associated changes in international food prices.

This article investigates how technology has influenced the size of armies. During the nineteenth century, the development of the railroad made it possible to field and support mass armies, significantly increasing the observed size of military forces. During the late twentieth century, further advances in technology made it possible to deliver explosive force from a distance and with precision, making mass armies less desirable. The authors find support for their technological account using a new data set covering thirteen great powers between 1600 and 2000. They find little evidence that the French Revolution was a watershed in terms of levels of mobilization.

Governments and multi-lateral donor organizations are increasingly targeting development aid to conflict affected areas with the hope that this aid will help government efforts to reduce conflict and stabilize these areas. 

The expectation is that implementing development projects such as roads, schools, and hospitals will increase popular support for the government – effectively  “winning hearts and minds” of the people- and reduce popular support for insurgents making it more difficult for them to recruit rebels and carry out attacks.

Joe Felter, a Senior Research Scholar at CISAC, with Benjamin Crost at the University of Illinois and Patrick Johnston from the RAND Corporation published Aid Under Fire: Development Projects and Civil Conflict in the June edition of the American Economic Review that challenges this conventional wisdom.

In this article, Felter and his coauthors provide evidence that a “winning hearts and minds” strategy can backfire in some cases. When insurgents believe that that the successful implementation of government sponsored development projects will lead to an increase in support for the government and undermine their position they have incentives to attack or otherwise sabotage them thus exacerbating conflict in the near term.  

Ironically, increases in violence associated with government sponsored development efforts can in some cases be interpreted as an indicator that these efforts are targeting insurgent vulnerabilities effectively.

This article adds to Felter’s previously published research on the challenges of stabilizing conflict areas through development aid and economic assistance. See

Modest, Secure and Informed: Successful Development in Conflict Zones with Eli Berman, Jacob Shapiro and Erin Troland in American Economic Review Papers and Proceedings 2013

Can Hearts and Minds be Bought? The Economics of Counterinsurgency in Iraq with Eli Berman and Jacob Shapiro in the Journal of Political Economy 2011

Do Working Men Rebel? Insurgency and Unemployment in Afghanistan, Iraq and the Philippines with Eli Berman, Jacob Shapiro and Michael Callen Journal of Conflict Resolution 2011.