جغرافیا، بهداشت، و سرعت توسعه دمو اقتصادی

This paper investigates the impact of subsistence consumption and extrinsic and intrinsic causes of child mortality on fertility and child expenditure. It offers a theory for why mankind multiplies at higher rates at geographically unfavorable, tropical locations. Placed into a macroeconomic framework this behavior creates an indirect channel through which geography shapes economic performance. It is explained why it are countries of low absolute latitude where we observe exceedingly slow (if not stalled) economic development and demographic transition.

As for every species, survival of humans is easier in some regions of the world and harder in others. In particular tropical regions – defined by an absolute latitude below 23.5° – provide an unfavorable location for a child to survive whereas survival is almost certain at latitudes of 40° and higher. This fact is visualized in Fig. 1.a which shows for 137 countries average absolute latitude against the probability for a child to survive its fifth birthday.1

The model offers an explanation for the observation that the pace of demographic transition is influenced by geographic location. In particular at tropical locations the pattern of demographic transition can look very differently compared to the experiences of the Western world. In fact, focussing on population growth alone, ongoing demographic transition can be so exceedingly slow that it looks like stagnation within a reasonable time-window (of, say, 50 years). Because it is visually indistinguishable, the situation may mistakenly be identified as poverty trap. In order to demonstrate these results, we consider the following experiment. Suppose there are three countries sharing the parameters of preference for consumption, family size, and child expenditure with the U.S. calibration from Fig. 4. Assume identical technologies for all three countries: α = 0.8 and gA = 0.04%. Given the low rate of technological progress, the population grows initially at a low equilibrium rate of 0.2% everywhere. The three countries differ in their extrinsic child survival rates, parameterized by b ∈ {0.004, 0.0025, 0.002}.