Collapse: How Societies Choose to Fail or Succeed (58 page)

factors made it in the interests of the shogun, daimyo, and peasants to man
age their forests sustainably. Equally obviously after the Meireki fire, those
factors made short-term overexploitation of forests foolish.

Of course, though, people with long-term stakes don't always act wisely.
Often they still prefer short-term goals, and often again they do things that are foolish in both the short term and the long term. That's what makes biography and history infinitely more complicated and less predictable than the courses of chemical reactions, and that's why this book doesn't preach
environmental determinism. Leaders who don't just react passively, who
have the courage to anticipate crises or to act early, and who make strong insightful decisions of top-down management really can make a huge dif
ference to their societies. So can similarly courageous, active citizens prac
ticing bottom-up management. The Tokugawa shoguns, and my Montana
landowner friends committed to the Teller Wildlife Refuge, exemplify the
best of each type of management, in pursuit of their own long-term goals
and of the interests of many others.

In thus devoting one chapter to these three success stories of the New
Guinea highlands, Tikopia, and Tokugawa Japan, after seven chapters mostly
on societies brought down by deforestation and other environmental prob
lems plus a few other success stories (Orkney, Shetland, Faeroes, Iceland),
I'm not implying that success stories constitute rare exceptions. Within the
last few centuries Germany, Denmark, Switzerland, France, and other west
ern European countries stabilized and then expanded their forested area by top-down measures, as did Japan. Similarly, about 600 years earlier, the
largest and most tightly organized Native American society, the Inca Empire
of the Central Andes with tens of millions of subjects under an absolute
ruler, carried out massive reafforestation and terracing to halt soil erosion,
increase crop yields, and secure its wood supplies.

Examples of successful bottom-up management of small-scale farming,
pastoral, hunting, or fishing economies also abound. One example that I
briefly mentioned in Chapter 4 comes from the U.S. Southwest, where Native American societies far smaller than the Inca Empire attempted many
different solutions to the problem of developing a long-lasting economy in a difficult environment. The Anasazi, Hohokam, and Mimbres solutions eventually came to an end, but the somewhat different Pueblo solution has
now been operating in the same region for over a thousand years. While the Greenland Norse disappeared, the Greenland Inuit maintained a self-

sufficient hunter-gatherer economy for at least 500 years, from their arrival by
a.d.
1200 until the disruptions caused by Danish colonization beginning
in
a.d.
1721. After the extinction of Australia's Pleistocene megafauna
around 46,000 years ago, Aboriginal Australians maintained hunter-gatherer
economies until European settlement in
a.d.
1788. Among the numerous,
self-sustaining, small-scale rural societies in modern times, especially well-
studied ones include communities in Spain and in the Philippines maintain
ing irrigation systems, and Swiss alpine villages operating mixed farming
and pastoral economies, in both cases for many centuries and with detailed
local agreements about managing communal resources.

Each of these cases of bottom-up management that I have just men
tioned involves a small society holding exclusive rights to all economic
activities on its lands. Interesting and more complex cases exist (or tradi
tionally existed) on the Indian subcontinent, where the caste system instead
operates to permit dozens of economically specialized sub-societies to share
the same geographic area by carrying out different economic activities.
Castes trade extensively with each other and often live in the same village
but are endogamous
—i.e., people generally marry within their caste. Castes
coexist by exploiting different environmental resources and lifestyles, such
as by fishing, farming, herding, and hunting/gathering. There is even finer
specialization, e.g., with multiple castes of fishermen fishing by different
methods in different types of waters. As in the case of Tikopians and of the
Tokugawa Japanese, members of the specialized Indian castes know that
they can count on only a circumscribed resource base to maintain them
selves, but they expect to pass those resources on to their children. Those
conditions have fostered the acceptance of very detailed societal norms by
which members of a given caste ensure that they are exploiting their re
sources sustainably.

The question remains why these societies of Chapter 9 succeeded while
most of the societies selected for discussion in Chapters 2-8 failed. Part of
the explanation lies in environmental differences: some environments are more fragile and pose more challenging problems than do others. We al
ready saw in Chapter 2 the multitude of reasons causing Pacific island envi
ronments to be more or less fragile, and explaining in part why Easter and
Mangareva societies collapsed while Tikopia society didn't. Similarly, the
success stories of the New Guinea highlands and Tokugawa Japan recounted
in this chapter involved societies that enjoyed the good fortune to be occupying relatively robust environments. But environmental differences aren't
the whole explanation, as proved by the cases, such as those of Greenland

PART
THREE

MODERN
SOCIETIES

CHAPTER
10

Malthus in Africa: Rwanda's Genocide

A dilemma
m
Events in Rwanda
■ More than ethnic hatred ■ Buildup in Kanama » Explosion in Kanama
it
Why it happened
■

W

hen 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 peo
ple. No matter how often we had already seen wildebeest moving across the
TV screen of
National Geographic
specials viewed in the comfort of our liv
ing 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 im
pact 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 popula
tion explosion has arisen despite Africa's being the continent inhabited by

humans much longer than any other, so that one might naively have ex
pected 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 cas
sava), broadening the agricultural base and increasing food production be
yond 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 exponen
tially, 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 people in the year 2105, and so on.
But improvements in food production add rather than multiply: this break
through increases wheat yields by 25%, that breakthrough increases yields by an additional 20%, etc. That is, there is a basic difference between how
population grows and how food production grows. When population grows,
the extra people added to the population also themselves reproduce
—as in compound interest, where the interest itself draws interest. That allows ex
ponential growth. In contrast, an increase in food yield does not then further increase yields, but instead leads only to arithmetic growth in food production. Hence a population will tend to expand to consume all avail
able food and never leave a surplus, unless population growth itself is halted
by famine, war, or disease, or else by people making preventive choices (e.g.,
contraception or postponing marriage). The notion, still widespread today, that we can promote human happiness
merely
by increasing food production, without a simultaneous reining-in of population growth, is doomed to
end in frustration—or so said Malthus.

The validity of his pessimistic argument has been much debated.
Indeed, there are modern countries that have drastically reduced their
population growth by means of voluntary (e.g., Italy and Japan) or

government-ordered (China) birth control. But modern Rwanda illustrates
a case where Malthus's worst-case scenario does seem to have been right.
More generally, both Malthus's supporters and his detractors could agree that population and environmental problems created by non-sustainable
resource use will ultimately get solved in one way or another: if not by pleas
ant means of our own choice, then by unpleasant and unchosen means, such
as the ones that Malthus initially envisioned.

A few months ago, while I was teaching a course to UCLA undergradu
ates on environmental problems of societies, I came to discuss the difficul
ties that regularly confront societies trying to reach agreements about environmental disputes. One of my students responded by noting that dis
putes could be, and frequently were, solved in the course of conflict. By that,
the student didn't mean that he favored murder as a means of settling dis
putes. Instead, he was merely observing that environmental problems often
do create conflicts among people, that conflicts in the U.S. often become re
solved in court, that the courts provide a perfectly acceptable means of dis
pute resolution, and hence that students preparing themselves for a career
of resolving environmental problems need to become familiar with the ju
dicial system. The case of Rwanda is again instructive: my student was fun
damentally correct about the frequency of resolution by conflict, but the conflict may assume nastier forms than courtroom processes.

In recent decades, Rwanda and neighboring Burundi have become syn
onymous in our minds with two things: high population, and genocide
(Plate 21). They are the two most densely populated countries in Africa,
and among the most densely populated in the world: Rwanda's average population density is triple even that of Africa's third most densely populated country (Nigeria), and 10 times that of neighboring Tanzania. Genocide in Rwanda produced the third largest body count among the world's
genocides since 1950, topped only by the killings of the 1970s in Cambodia
and of 1971 in Bangladesh (at the time East Pakistan). Because Rwanda's
total population is 10 times smaller than that of Bangladesh, the scale of Rwanda's genocide, measured in proportion to the total population killed,
far exceeds that of Bangladesh and stands second only to Cambodia's. Bu
rundi's genocide was on a smaller scale than Rwanda's, yielding "only" a few
hundred thousand victims. That still suffices to place Burundi seventh in
the world since 1950 in its number of victims of genocide, and tied for fourth place in proportion of the population killed.