Collapse_ How Societies Choose to Fail or Succeed - Jared Diamond [193]
PART THREE
MODERN SOCIETIES
CHAPTER 10
Malthus in Africa: Rwanda’s Genocide
A dilemma ��� Events in Rwanda ■ More than ethnic hatred ■ Buildup in Kanama ■ Explosion in Kanama ■ Why it happened ■
When my twin sons were 10 years old and again when they were 15, my wife and I took them on family vacations to East Africa. Like many other tourists, the four of us were overwhelmed by our firsthand experience of Africa’s famous large animals, landscapes, and people. No matter how often we had already seen wildebeest moving across the TV screen of National Geographic specials viewed in the comfort of our living rooms, we were unprepared for the sight, sound, and smell of millions of them on the Serengeti Plains, as we sat in a Land Rover surrounded by a herd stretching from our vehicle to the horizon in all directions. Nor had television prepared us for the immense size of Ngorongoro Crater’s flat and treeless floor, and for the steepness and height of its inner walls down which one drives from a tourist hotel perched on the rim to reach that floor.
East Africa’s people also overwhelmed us, with their friendliness, warmth to our children, colorful clothes—and their sheer numbers. To read in the abstract about “the population explosion” is one thing; it is quite another thing to encounter, day after day, lines of African children along the roadside, many of them about the same size and age as my sons, calling out to passing tourist vehicles for a pencil that they could use in school. The impact of those numbers of people on the landscape is visible even along stretches of road where the people are off doing something else. In pastures the grass is sparse and grazed closely by herds of cattle, sheep, and goats. One sees fresh erosion gullies, in whose bottoms run streams brown with mud washed down from the denuded pastures.
All of those children add up to rates of human population growth in East Africa that are among the highest in the world: recently, 4.1% per year in Kenya, resulting in the population doubling every 17 years. That population explosion has arisen despite Africa’s being the continent inhabited by humans much longer than any other, so that one might naïvely have expected Africa’s population to have leveled off long ago. In fact, it has been exploding recently for many reasons: the adoption of crops native to the New World (especially corn, beans, sweet potatoes, and manioc, alias cassava), broadening the agricultural base and increasing food production beyond that previously possible with native African crops alone; improved hygiene, preventive medicine, vaccinations of mothers and children, antibiotics, and some control of malaria and other endemic African diseases; and national unification and the fixing of national boundaries, thereby opening to settlement some areas that were formerly no-man’s lands fought over by adjacent smaller polities.
Population problems such as those of East Africa are often referred to as “Malthusian,” because in 1798 the English economist and demographer Thomas Malthus published a famous book in which he argued that human population growth would tend to outrun the growth of food production. That’s because (Malthus reasoned) population growth proceeds exponentially, while food production increases only arithmetically. For instance, if a population’s doubling time is 35 years, then a population of 100 people in the year 2000, if it continues to grow with that same doubling time, will have doubled in the year 2035 to 200 people, who will in turn double to 400 people in 2070, who will double to 800