We have estimated the effect of the introduction of the potato on Old World population growth and urbanization. The nutritional and caloric superiority of the potato, and its diffusion from the New World to the Old, allows us to estimate causal effects using a difference-in-differences estimation strategy. According to our most conservative estimates, the introduction of the potato explains 22% of the observed post-1700 increase in population growth. These results show that food and nutrition matter. By increasing the nutritional carrying capacity of land they can have large effects on population.To the extent that urbanization serves as a measure of the shift from rural agriculture to urban manufacturing, our estimates also provide historic evidence of the importance of agricultural productivity for economic development. According to our estimates, the introduction of the potato explains 47% of the post-1700 increase in the average urbanization rate. Our estimates suggest that increased agricultural productivity can play a signiﬁcant part in promoting the rise of urban centers, industry, and economic development.
Of course, one would expect that a crop like the potato, with a clear caloric superiority over alternatives, would quickly drive those alternatives off the land, leading to dependence on a monoculture. This, in turn, would make potato countries exceedingly vulnerable to shocks to the potato crop—like, say, blight.