contradicted by the recent rapid economic advance of
countries such as Singapore, Malaysia, and Botswana, is
still forcefully advocated by some, such as the economist
Jeffrey Sachs. The modern version of this view emphasizes
not the direct effects of climate on work effort or thought
processes, but two additional arguments: first, that tropical
diseases, particularly malaria, have very adverse
consequences for health and therefore labor productivity;
and second, that tropical soils do not allow for productive
agriculture. The conclusion, though, is the same: temperate
climates have a relative advantage over tropical and
semitropical areas.
World inequality, however, cannot be explained by
climate or diseases, or any version of the geography
hypothesis. Just think of Nogales. What separates the two
parts is not climate, geography, or disease environment,
but the U.S.-Mexico border.
If the geography hypothesis cannot explain differences
between the north and south of Nogales, or North and
South Korea, or those between East and West Germany
before the fall of the Berlin Wall, could it still be a useful
theory for explaining differences between North and South
America? Between Europe and Africa? Simply, no.
History illustrates that there is no simple or enduring
connection between climate or geography and economic
success. For instance, it is not true that the tropics have
always been poorer than temperate latitudes. As we saw in
the last chapter, at the time of the conquest of the Americas
by Columbus, the areas south of the Tropic of Cancer and
north of the Tropic of Capricorn, which today include
Mexico, Central America, Peru, and Bolivia, held the great
Aztec and Inca civilizations. These empires were politically
centralized and complex, built roads, and provided famine
relief. The Aztecs had both money and writing, and the
Incas, even though they lacked both these two key
technologies, recorded vast amounts of information on
knotted ropes called quipus. In sharp contrast, at the time of
the Aztecs and Incas, the north and south of the area
inhabited by the Aztecs and Incas, which today includes the
United States, Canada, Argentina, and Chile, were mostly
inhabited by Stone Age civilizations lacking these
technologies. The tropics in the Americas were thus much