Rural Push, Urban Pull and... Urban Push? New Historical Evidence from Developing Countries

Standard models explain urbanization by rural-urban migration in response to an (expected) urban-rural wage gap. The Green Revolution and rural poverty constitute rural push factors of migration. The Industrial Revolution and the urban bias are urban pull factors. This paper offers an additional demographic mechanism, based on internal urban population growth, i.e. an urban push. Using newly compiled historical data on urban birth and death rates for 7 countries from Industrial Europe (1800-1910) and 33 developing countries (1960-2010), we show that many cities of today's developing world are "mushroom cities" vs. the "killer cities" of Industrial Europe; fertility is high, while mortaility is much lower. The high rates of urban natural increase have then accelerated urban growth and urbanization in developing countries, with urban populations now doubling every 18 years (15 years in Africa), compared to every 35 years in Industrial Europe. This is further found to be associated with higher urban congestion, possibly mitigating the benefits from agglomeration and providing further insights into the phenomenon of urbanizatino without growth. Both migration and urban demographics must be considered in debating urbanization.