“…Recent work, then, has used natural experiments such as the eradication of endemic diseases (Bleakley, 2007) or variation over time in temperature and rainfall (Brückner and Ciccone, 2011;Dell et al, 2012). Abrupt and persistent changes in climate have precipitated economic collapse through lowered agricultural productivity, depopulation, the decline of cities and the weakening of states (Chaney, 2013;DeMenocal et al, 2001;Diamond, 2005;Haug et al, 2003;Hornbeck, 2012;Weiss and Bradley, 2001).…”