The Wealth and Poverty of Nations
"To be sure, geography is only one factor in play here. Some scholars blame technology and the rich countries that have developed it: they are charged with inventing methods suited to temperate climates, so that potentially fertile tropical soil remains fallow. Others accuse the colonial powers of disrupting the equatorial societies, so that they have lost control of their environment. Thus the slave trade, by depopulating large areas and allowing them to revert to bush, is said to have encouraged the tsetse fly and the spread of trypanosomiasis (sleeping sickness). Most writers prefer to say nothing on the subject.
One must not take that easy way out. The historian may not erase or rewrite the past to make it more pleasing; and the economist, whose easy assumption that every country is destined to develop sooner or later, must be ready to look hard at failure...
In general the discomfort of heat exceeds that of cold. We all know the fable of the sun and wind. One deals with cold by putting on clothing, by building or finding shelter, by making fire. These techniques go back tens of thousands of years and account for the early dispersion of humanity from an African origin to colder climes. Heat is another story...
The easiest way to reduce this waste problem is not to generate heat; in other words, keep still and don't work. Hence such social adaptations as the siesta, which is designed to keep people inactive in the heat of midday...
Slavery makes other people do the hard work. It is no accident that slave labor has historically been associated with tropical and semitropical climes. The same holds for division of labor by gender: in warm lands particularly... The aim is to shift the work and pain to those not able to say no.
The ultimate answer to heat has been air conditioning. But that came in very late--really after World War II... In America, air conditioning made possible the economic prosperity of the New South. Without it, cities like Atlanta, Houston, and New Orleans would still be sleepy-time towns...
Heat, especially year-round heat, has an even more deleterious consequence: it encourages the proliferation of life forms hostile to man. Insects swarm as the temperature rises, and parasites within them mature and breed more rapidly. The result is faster transmission of disease and development of immunities to countermeasures... Winter, then, in spite of what poets may say about it, is the great friend of humanity: the silent white killer, slayer of insects and parasites, cleanser of pests...
Personal experiences can be misleading, if only because of the variance among individuals. One person's discomfort is another's pleasure. Still, the law of heat exhaustion applies to all, and few manage to work at full capacity when hot and wet. Here is a Bangladeshi diplomat recalling his own experience and that of compatriots when visiting temperate climes:
"In countries like India, Pakistan, Indonesia, Nigeria and Ghana I have always felt enervated by the slightest physical or mental exertion, whereas in the UK, France, Germany or the US I have always felt reinforced and stimulated by the temperate climate, not only during long stays, but even during brief travels. And I know that all tropical peoples visiting temperate countries have had a similar experience. I have also seen hundreds of people from the temperate zone in the tropics feeling enervated and exhausted whenever they were not inside an air-conditioned room.
"In India and other tropical countries I have noticed farmers, industrial labourers, and in fact all kinds of manual and office workers working in slow rhythm with long and frequent rest pauses. But in the temperate zone I have noticed the same classes of people working in quick rhythm with great vigour and energy, and with very few rest pauses. I have known from personal experience and the experience of other tropical peoples in the temperate zone that this spectacular difference in working energy and efficiency could not be due entirely or even mainly to different levels of nutrition.""
Addendum: This is from David S. Landes, 1998
Keywords: Harvard, no geography department