To what extent do natural environments explain political development? A lot, according to a recent paper by Stephen Haber and Victor Menaldo. They find that rainfall and democracy go together like porridge and Goldilocks – to get democracy to flourish, it shouldn’t be too wet or too dry:
Why are some societies characterized by enduring democracy while other societies are persistently autocratic? We show that there is a systematic, non-linear relationship between rainfall levels and regime types in the post-World War II world: stable democracies overwhelmingly cluster in a band of moderate rainfall (550 to 1300 mm of precipitation per year); persistent autocracies overwhelmingly cluster in deserts and semi-arid environments (0 to 550 mm per year) and in the tropics (above 1300 mm per year). We also show that rainfall does not work on regime types directly, but does so through the its impact on the level and distribution of human capital. Specifically, crops that are both easily storable and exhibit modest economies of scale in production grow well under moderate amounts of rainfall. The modal production unit is a family farm that can accumulate surpluses. In such an economy there are incentives to make intergenerational investments in human capital. A high level and broad distribution of human capital makes democratic consolidation more likely.
ht: Roger K., who referred me to a recent Amity Shlaes column that cites this research.