Rain, Riches, and Empire: The Relationship between Nations Ruling Distant Lands, Nations of Great Wealth, and Regions of Regular Moderate Atmospheric Precipitation

Abstract

Abstract Two of the great questions of human history and economics are why some nations held far-flung empires and why some presently enjoy great wealth. One factor that should be included in the inevitably multifactorial answer to these questions is regular moderate precipitation (precipitation with an average rate between 30 and 120 mm for each month). Only a small proportion of Earth’s surface has regular moderate precipitation, and most of that area is in Europe and eastern North America. Strikingly, of the 13 nations that held geographically discontinuous multicontinental transoceanic empires, 12 overlap with regions of regular moderate precipitation. Similarly, of the 20 nations with the greatest per capita GDP in 2015, 16 coincide with regions of regular moderate precipitation. These relationships are presumably rooted in the greater success, or lesser inhibition, of human construction of infrastructure, husbandry of livestock, and cultivation of crops, some combination of which likely allowed industrialization, projection of geopolitical power, and accumulation of wealth. One instructive example is that of China, which has a climate superficially like that of Europe and eastern North America but no regions of regular moderate rainfall, and which neither developed an overseas empire nor is among the world’s nations with greatest per capita GDP. Furthermore, concentration of nations holding empires and wealth in the Northern Hemisphere and their absence from the south can be linked to the coincidence that the Southern Hemisphere’s latitudinal zone of regular moderate rainfall is over the Southern Ocean, where there is little land on which human societies could have enjoyed the benefits of that supportive climate.