Collapse: How Societies Choose to Fail or Succeed

by Jared Diamond

  The rise of silviculture in Japan was facilitated by the fairly uniform institutions and methods over the whole country. Unlike the situation in Europe, divided at that time among hundreds of principalities or states, Tokugawa Japan was a single country governed uniformly. While southwestern Japan is subtropical and northern Japan is temperate, the whole country is alike in being wet, steep, erodable, of volcanic origins, and divided between steep forested mountains and flat cropland, thus providing some ecological uniformity in conditions for silviculture. In place of Japan’s tradition of multiple use of forests, under which the elite claimed the timber and the peasants gathered fertilizer, fodder, and fuel, plantation forest became specified as being for the primary purpose of timber production, other uses being allowed only insofar as they did not harm timber production. Forest patrols guarded against illegal logging activity. Plantation forestry thereby became widespread in Japan between 1750 and 1800, and by 1800 Japan’s long decline in timber production had been reversed.

  An outside observer who visited Japan in 1650 might have predicted that Japanese society was on the verge of a societal collapse triggered by catastrophic deforestation, as more and more people competed for fewer resources. Why did Tokugawa Japan succeed in developing top-down solutions and thereby averting deforestation, while the ancient Easter Islanders, Maya, and Anasazi, and modern Rwanda (Chapter 10) and Haiti (Chapter 11) failed? This question is one example of the broader problem, to be explored in Chapter 14, why and at what stages people succeed or fail at group decision-making.

  The usual answers advanced for Middle and Late Tokugawa Japan’s success—a supposed love for Nature, Buddhist respect for life, or a Confucian outlook—can be quickly dismissed. In addition to those simple phrases not being accurate descriptions of the complex reality of Japanese attitudes, they did not prevent Early Tokugawa Japan from depleting Japan’s resources, nor are they preventing modern Japan from depleting the resources of the ocean and of other countries today. Instead, part of the answer involves Japan’s environmental advantages: some of the same environmental factors already discussed in Chapter 2 to explain why Easter and several other Polynesian and Melanesian islands ended up deforested, while Tikopia, Tonga, and others did not. People of the latter islands have the good fortune to be living in ecologically robust landscapes where trees regrow rapidly on logged soils. Like robust Polynesian and Melanesian islands, Japan has rapid tree regrowth because of high rainfall, high fallout of volcanic ash and Asian dust restoring soil fertility, and young soils. Another part of the answer has to do with Japan’s social advantages: some features of Japanese society that already existed before the deforestation crisis and did not have to arise as a response to it. Those features included Japan’s lack of goats and sheep, whose grazing and browsing activities elsewhere have devastated forests of many lands; the decline in number of horses in Early Tokugawa Japan, due to the end of warfare eliminating the need for cavalry; and the abundance of seafood, relieving pressure on forests as sources of protein and fertilizer. Japanese society did make use of oxen and horses as draft animals, but their numbers were allowed to decrease in response to deforestation and loss of forest fodder, to be replaced by people using spades, hoes, and other devices.

  The remaining explanations constitute a suite of factors that caused both the elite and the masses in Japan to recognize their long-term stake in preserving their own forests, to a degree greater than for most other people. As for the elite, the Tokugawa shoguns, having imposed peace and eliminated rival armies at home, correctly anticipated that they were at little risk of a revolt at home or an invasion from overseas. They expected their own Tokugawa family to remain in control of Japan, which in fact it did for 250 years. Hence peace, political stability, and well-justified confidence in their own future encouraged Tokugawa shoguns to invest in and to plan for the long-term future of their domain: in contrast to Maya kings and to Haitian and Rwandan presidents, who could not or cannot expect to be succeeded by their sons or even to fill out their own term in office. Japanese society as a whole was (and still is) relatively homogeneous ethnically and religiously, without the differences destabilizing Rwandan society and possibly also Maya and Anasazi societies. Tokugawa Japan’s isolated location, negligible foreign trade, and renunciation of foreign expansion made it obvious that it had to depend on its own resources and wouldn’t solve its needs by pillaging another country’s resources. By the same token, the shogun’s enforcement of peace within Japan meant that people knew that they couldn’t meet their timber needs by seizing a Japanese neighbor’s timber. Living in a stable society without input of foreign ideas, Japan’s elite and peasants alike expected the future to be like the present, and future problems to have to be solved with present resources.

  The usual assumption of Tokugawa well-to-do peasants, and the hope of poorer villagers, were that their land would pass eventually to their own heirs. For that and other reasons, the real control of Japan’s forests fell increasingly into the hands of people with a vested long-term interest in their forest: either because they thus expected or hoped their children would inherit the rights to its use, or because of various long-term lease or contract arrangements. For instance, much village common land became divided into separate leases for individual households, thereby minimizing the tragedies of the common to be discussed in Chapter 14. Other village forests were managed under timber sale agreements drawn up long in advance of logging. The government negotiated long-term contracts on government forest land, dividing eventual timber proceeds with a village or merchant in return for the latter managing the forests. All these political and social factors made it in the interests of the shogun, daimyo, and peasants to manage 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 difference to their societies. So can similarly courageous, active citizens practicing 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 problems 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 western 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 Nor
se 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 maintaining 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 mentioned involves a small society holding exclusive rights to all economic activities on its lands. Interesting and more complex cases exist (or traditionally 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 themselves, 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 resources 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 already saw in Chapter 2 the multitude of reasons causing Pacific island environments 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 and the U.S. Southwest, in which one society succeeded while one or more societies practicing different economies in the same environment failed. That is, not only the environment, but also the proper choice of an economy to fit the environment, is important. The remaining large piece of the puzzle involves whether, even for a particular type of economy, a society practices it sustainably. Regardless of the resources on which the economy rests—farmed soil, grazed or browsed vegetation, a fishery, hunted game, or gathered plants or small animals—some societies evolve practices to avoid overexploitation, and other societies fail at that challenge. Chapter 14 will consider the types of mistakes that must be avoided. First, however, the next four chapters will examine four modern societies, for comparison with the past societies that we have been discussing since Chapter 2.

  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 people in the year 2105, and so on. But improvements in food production add rather than multiply: this breakthrough 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 exponential 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 available 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 pleasant 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 undergraduates on environmental problems of societies, I came to discuss the difficulties that regularly confront societies trying to reach agreements about environmental disputes. One of my students responded by noting that disputes 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 disputes. Instead, he was merely observing that environmental problems often do create conflicts among people, that conflicts in the U.S. often become resolved in court, that the courts provide a perfectly acceptable means of dispute resolution, and hence that students preparing themselves for a career of resolving environmental problems need to become familiar with the judicial system. The case of Rwanda is again instructive: my student was fundamentally correct about the frequency of resolution by conflict, but the conflict may assume nastier forms than courtroom processes.