biostudies-literatureRoche KRNational Science Foundation1935-1940https://www.ebi.ac.uk/biostudies/studies/S-EPMC6994975biostudies-literatureUnknown117(4)A growing empirical literature associates climate anomalies with increased risk of violent conflict. This association has been portrayed as a bellwether of future societal instability as the frequency and intensity of extreme weather events are predicted to increase. This paper investigates the theoretical foundation of this claim. A seminal microeconomic model of opportunity costs-a mechanism often thought to drive climate-conflict relationships-is extended by considering realistic changes in the distribution of climate-dependent agricultural income. Results advise caution in using empirical associations between short-run climate anomalies and conflicts to predict the effect of sustained shifts in climate regimes: Although war occurs in bad years, conflict may decrease if agents expect moProceedings of the National Academy of Sciences of the United States of AmericaClimate change and the opportunity cost of conflict.PMC6994975ICER 1824951Muller-Itten MDralle DNBolster DMuller MFRoche KRfalseClimate change and the opportunity cost of conflict.A growing empirical literature associates climate anomalies with increased risk of violent conflict. This association has been portrayed as a bellwether of future societal instability as the frequency and intensity of extreme weather events are predicted to increase. This paper investigates the theoretical foundation of this claim. A seminal microeconomic model of opportunity costs-a mechanism often thought to drive climate-conflict relationships-is extended by considering realistic changes in the distribution of climate-dependent agricultural income. Results advise caution in using empirical associations between short-run climate anomalies and conflicts to predict the effect of sustained shifts in climate regimes: Although war occurs in bad years, conflict may decrease if agents expect mo2020-01-01T00:00:00Z2020 Jan2025-04-06T15:16:55.143Z2025-04-06T15:16:55.143ZS-EPMC69949753193243310.1073/pnas.1914829117