Asylum Applications Respond to Temperature Fluctuations

Anouch Missirian and Wolfram Schlenker

Science Vol 358, Issue 6370, 22 December 2017


There is ongoing debate as to whether climate change has contributed to, and will amplify, migration flows to the European Union from war-affected countries such as Syria, Afghanistan or Iraq. For example, a 2015 study showed that the Syrian conflict was preceded by a record drought that led to lower agricultural yields and forced farmers to migrate to urban areas. The paper explores the effects of climate change on distress-driven migration by examining how recent weather variations (from 2000 to 2014) in 103 countries translated into asylum applications to the European Union. The authors find a U-shaped relationship between the weather in a source country and the number of accepted asylum applications, i.e. temperatures that are too low or too high will lead to more numerous asylum applications. Total precipitation, on the other hand, is not an important predictor of migration (consistent with research that indicates that temperature rather than precipitation is a stronger predictor of conflict). The authors suggest several mechanisms driving the sensitivity of asylum applications to temperature anomalies: (1) a strong nonlinear relationship between agricultural yields and temperature, i.e. hot and cold temperatures reduce yield; (2) gross domestic product (GDP) growth rates have been found to be very sensitive to temperature, even on the nonagricultural components of GDP and even in industrialized countries; and (3) aggressive behavior increases with temperature. The authors conclude that climate change, especially continued warming, will add another “threat multiplier” that induces people to seek refuge abroad.