Is geography destiny? One strand of development economics, represented most vigorously by Jeffrey Sachs, believes so. Landlocked, mountainous states, like, say, Bolivia, face much larger obstacles in achieving economic growth than do countries with easy access to seaports, and navigable rivers. Sachs particularly likes to apply this theory to his current passion, Africa, because he thinks it provides a justification for increasing foreign aid. If the desperate straits of some African countries are due to their geographic constraints, instead of crappy institutions or government corruption, then there's no fundamental reason why external inputs -- new roads, railways, etc. -- can't overcome the backwardness inflicted by the contours of the land.

But a fascinating new paper, "Ruggedness: The Blessing of Bad Geography in Africa," muddies the waters by arguing that sometimes bad can be good. (Thanks to Trade Diversion for the link. A simplified version of the argument can be found here.)

Nathan Nunn and Diego Pugo look first at the historical devastation wrought by the slave trade on Africa, and come up with two observations.

The first, which is not original to them, is that those countries that lost the largest portions of their population to the slave trade are among the most underdeveloped states in Africa today. So history is destiny. But we all knew that.

The second point is that the regions in which Africans tended to escape the depredations of slavery tended to be characterized by a greater degree of "ruggedness." It was easier to hide from the slavers in the hills. The authors do a ton of number-crunching to prove that over the centuries, Africans fleeing from the slave trade tended to congregate in more rugged regions.

The upshot? "The combination of the threat of slave raids with the availability of areas with varying ruggedness has resulted in a concentration of population in particularly rugged areas that has persisted until today."

Which means that bad geography has had both a positive and negative effect on the economic development of Africa. By insulating some Africans from the disastrous effects of the slave trade, it had a huge positive effect, significantly boosting incomes.

But the contemporaneous negative effect on economic development imposed by rugged terrain also exists. So those Africans that escaped the frying pan of slavery ended up in the fire of bad geography. History and geography: a double dose of destiny.