Africa has recently known dramatic urban growth, which is good news if urbanization drives growth. Yet, the agglomeration effects story was built on manufacturing and tradable services, two sectors under-represented in Africa. The authors develop another story where urbanization is pushed by rural windfalls, with a case study on cocoa production and cities in Ivory Coast and Ghana. Combining decadal district-level data on cocoa production and cities from 1901 to 2000, they show how cities follow the cocoa front. They use the fact that cocoa is produced by ”eating” the virgin forest: (a) only forested areas are suitable to cocoa, i.e. the south of both countries, (b) for agronomic reasons, cocoa farmers move to a new forest every 25 years, thus causing regional cycles, and (c) the cocoa front started from the (South-)East of both countries.
Jedwab, R. African cities and the structural transformation : evidence from Ghana and Ivory Coast. (2010)