Modeling periodic waves of integration in the Afro-Eurasian world-system
Most people assume that the current period of global connectivity is a unique and unprecedented development in human history. Although the breadth and depth of the globalization that began after World War II is indeed unrivaled, in the past humanity has experienced other periods of heightened longdistance connectivity that resulted in massive long-distance movements of goods, people, ideas, genes, cultivars, and pathogens (Chase-Dunn and Hall 1997; Gills and Thompson 2006). One example of a previous “globalization” is the Age of Discovery of the sixteenth century, during which all major population centers of the world, both in Afro-Eurasia and the Americas, were connected by trade and conquest, which resulted in a massive interchange of cultural elements, genes, and pathogens, known as the Columbian Exchange (Crosby 1972). The globalization of the sixteenth century was followed by the Crisis of the Seventeenth Century, which was also truly global in nature. The wave of state collapse rolled over the whole of Eurasia (with the possible exception of South Asia). Populations declined in such far-ﬂung regions as Spain, Russia, and China. But the demographic catastrophe was even greater in the New World – the Native American population may have declined to perhaps ten percent of the pre-Columbian level. So massive was the world’s population collapse that we can detect it in the decline of global emissions of greenhouse gasses (CO2 and CH4), which even then were affected by anthropogenic activities. According to at least one theory, this decline in greenhouse gas concentration may have caused the Little Ice Age of the eighteenth century (Ruddiman 2005).