Collapse

by Diamond, Jared

  Courageous, successful, long-term planning also characterizes some governments and some political leaders, some of the time. Over the last 30 years a sustained effort by the U.S. government has reduced levels of the six major air pollutants nationally by 25%, even though our energy consumption and population increased by 40% and our vehicle miles driven increased by 150% during those same decades. The governments of Malaysia, Singapore, Taiwan, and Mauritius all recognized that their long-term economic well-being required big investments in public health to prevent tropical diseases from sapping their economies; those investments proved to be a key to those countries’ spectacular recent economic growth. Of the former two halves of the overpopulated nation of Pakistan, the eastern half (independent since 1971 as Bangladesh) adopted effective family planning measures to reduce its rate of population growth, while the western half (still known as Pakistan) did not and is now the world’s sixth most populous country. Indonesia’s former environmental minister Emil Salim, and the Dominican Republic’s former president Joaquín Balaguer, exemplify government leaders whose concern about chronic environmental dangers made a big impact on their countries. All of these examples of courageous long-term thinking in both the public sector and the private sector contribute to my hope.

  The other crucial choice illuminated by the past involves the courage to make painful decisions about values. Which of the values that formerly served a society well can continue to be maintained under new changed circumstances? Which of those treasured values must instead be jettisoned and replaced with different approaches? The Greenland Norse refused to jettison part of their identity as a European, Christian, pastoral society, and they died as a result. In contrast, Tikopia Islanders did have the courage to eliminate their ecologically destructive pigs, even though pigs are the sole large domestic animal and a principal status symbol of Melanesian societies. Australia is now in the process of reappraising its identity as a British agricultural society. The Icelanders and many traditional caste societies of India in the past, and Montana ranchers dependent on irrigation in recent times, did reach agreement to subordinate their individual rights to group interests. They thereby succeeded in managing shared resources and avoiding the tragedy of the commons that has befallen so many other groups. The government of China restricted the traditional freedom of individual reproductive choice, rather than let population problems spiral out of control. The people of Finland, faced with an ultimatum by their vastly more powerful Russian neighbor in 1939, chose to value their freedom over their lives, fought with a courage that astonished the world, and won their gamble, even while losing the war. While I was living in Britain from 1958 to 1962, the British people were coming to terms with the outdatedness of cherished long-held values based on Britain’s former role as the world’s dominant political, economic, and naval power. The French, Germans, and other European countries have advanced even further in subordinating to the European Union their national sovereignties for which they used to fight so dearly.

  All of these past and recent reappraisals of values that I have just mentioned were achieved despite being agonizingly difficult. Hence they also contribute to my hope. They may inspire modern First World citizens with the courage to make the most fundamental reappraisal now facing us: how much of our traditional consumer values and First World living standard can we afford to retain? I already mentioned the seeming political impossibility of inducing First World citizens to lower their impact on the world. But the alternative, of continuing our current impact, is more impossible. This dilemma reminds me of Winston Churchill’s response to criticisms of democracy: “It has been said that Democracy is the worst form of government except all those other forms that have been tried from time to time.” In that spirit, a lower-impact society is the most impossible scenario for our future—except for all other conceivable scenarios.

  Actually, while it won’t be easier to reduce our impact, it won’t be impossible either. Remember that impact is the product of two factors: population, multiplied times impact per person. As for the first of those two factors, population growth has recently declined drastically in all First World countries, and in many Third World countries as well—including China, Indonesia, and Bangladesh, with the world’s largest, fourth largest, and ninth largest populations respectively. Intrinsic population growth in Japan and Italy is already below the replacement rate, such that their existing populations (i.e., not counting immigrants) will soon begin shrinking. As for impact per person, the world would not even have to decrease its current consumption rates of timber products or of seafood: those rates could be sustained or even increased, if the world’s forests and fisheries were properly managed.

  My remaining cause for hope is another consequence of the globalized modern world’s interconnectedness. Past societies lacked archaeologists and television. While the Easter Islanders were busy deforesting the highlands of their overpopulated island for agricultural plantations in the 1400s, they had no way of knowing that, thousands of miles to the east and west at the same time, Greenland Norse society and the Khmer Empire were simultaneously in terminal decline, while the Anasazi had collapsed a few centuries earlier, Classic Maya society a few more centuries before that, and Mycenean Greece 2,000 years before that. Today, though, we turn on our television sets or radios or pick up our newspapers, and we see, hear, or read about what happened in Somalia or Afghanistan a few hours earlier. Our television documentaries and books show us in graphic detail why the Easter Islanders, Classic Maya, and other past societies collapsed. Thus, we have the opportunity to learn from the mistakes of distant peoples and past peoples. That’s an opportunity that no past society enjoyed to such a degree. My hope in writing this book has been that enough people will choose to profit from that opportunity to make a difference.

  AFTERWORD

  ANGKOR’S RISE AND FALL

  Questions about Angkor ■ Angkor’s environment ■ Angkor’s rise ■ The great city ■ Magnificent engineering ■ Angkor’s decline ■

  In 2008 I finally fulfilled a long-held dream of visiting the ruins of the medieval Southeast Asian city of Angkor in modern Cambodia. While I already knew that Angkor was big, no advance reading could have prepared me for experiencing at first hand the reality of its enormous scale. At its peak around a thousand years ago, it was the world’s most extensive city, among the most populous ones, and the capital of the largest and most powerful empire in Southeast Asia (the Khmer Empire). Its temples, such as Angkor Wat, include the largest religious monuments of the pre-modern world. Along with China’s Great Wall, Angkor’s large size makes it one of the ancient constructions most readily visible from space.

  Yet, by the 19th century there remained only about eight small villages dispersed over the central area formerly covered by this vast city. Cambodia today has become Southeast Asia’s poorest country. I know of no modern nation so nostalgically identified with the vanished glory of its archaeological past as is Cambodia, whose national flag displays an image of Angkor. The devolution of a sprawling metropolis into a largely empty landscape with scattered villages surely deserves to be termed a collapse. How did an environment initially supporting poor farmers spawn such a huge city and empire, and then fade again?

  When I published my book Collapse in 2005, I devoted only four sentences to Angkor because too little information was available then to tell a coherent story of the city’s collapse. Now, thanks to a flood of recent information from aerial radar surveys, ground surveys, excavations, and tree-ring measurements, we understand better what happened, even though many questions remain unanswered. It turns out that Angkor was not a unique phenomenon, as it at first seems. It was “just” the largest example of a type of city that no longer exists today but that formerly occurred more widely in seasonally wet tropical environments. That now unfamiliar type consisted of a low-density city, much more spread out than even my notoriously diffuse home city of Los Angeles: a city with farmland and farmhouses in close proximity to palace
s and temples, with people living at lower population densities than in our familiar modern cities that are all city and no farmland, but living at higher densities than in densely populated purely rural modern landscapes. Other examples of such low-density cities besides Angkor used to exist in Sri Lanka, Java, Thailand, Vietnam, and Myanmar. They existed especially in the Maya homeland of Mexico and Honduras, which supported Tikal, Copán, and the other great Maya cities that are the most familiar examples of this now vanished urban model. But even Tikal, the largest well-surveyed Maya city, was only about one-fifth of Angkor in extent. All of these low-density cities collapsed before they could be visited and described by Europeans. Could understanding of Angkor’s decline also illuminate the Classic Lowland Maya collapses that I described in Chapter 5?

  In the back of my mind as I visited Angkor was another question about its broader relevance. Sadly, Cambodia today is famous not only for its glorious ancient past, but also for its horrible recent past. From 1975 to 1979, under the paranoid dictatorship of Pol Pot and his Khmer Rouge, Cambodia was the site of the largest genocide since World War II, when Cambodians killed over a million of their fellow Cambodians, somewhere between one-seventh and one-third of their country’s entire population. While some victims were “merely” starved to death, others were tortured to death, or killed by their own parents. My Cambodian guides at Angkor in 2008 included one man who had lived through the horrors of Pol Pot and reluctantly answered our questions about what it was like then. Any people with any hint of usefulness for anything other than being a farm laborer—people wearing eyeglasses, people able to speak a second language besides Khmer, people with education—were killed. In a radical remaking of Cambodian society that dwarfed even the re-makings of North Korea and Albania and sought to turn back the clock a thousand years to the days of Angkor, cities were evacuated; money, religion, markets, private property, and businesses were abolished; hospitals, schools, and stores were closed; no books or newspapers could be published; and everyone had to wear black clothes, eat in communal kitchens, and be a rice farmer.

  Yet visitors today are struck by Cambodians as being nice, meek, gentle, peaceful people. How could people normally so mild have seesawed into such thoroughgoing savagery? Underneath that meek exterior, many Cambodians must have been seething with repressed fury. Is there anything about Cambodia’s history, and about the world society that enabled Cambodians to erect such a mighty city and empire, that could help us understand the plight and the explosion of modern Cambodia?

  Several features of the environment in which the Khmer Empire developed are crucial for understanding the empire’s rise and fall and its capital’s glory. At its maximum extent, the empire controlled one-third of mainland Southeast Asia. While its heartland was the basin of the Lower Mekong River in Cambodia, it expanded to encompass much of the territory of the adjacent modern countries of Vietnam, Laos, and Thailand between latitudes 9 and 20 degrees north. As modern Americans who fought there during the Vietnam War remember painfully well, this is a hot tropical environment in which temperatures are almost constantly above 70 degrees Fahrenheit, even at dawn after the coldest night of the coldest month of the year. Warm clothes and fires for warmth are only rarely necessary.

  Angkor’s major environmental challenges were related to rain and water. The area has a monsoon climate, a phrase that evokes images of torrential rain. Actually, the mean annual rainfall of Angkor is only 59 inches, which is barely higher than that of New York City. Compared to some of my New Guinea study sites and my home in Los Angeles, with annual rainfalls of 400 and 15 inches respectively, Angkor is neither especially wet nor especially dry.

  Instead, Angkor’s water problems stem from the fact that rainfall varies predictably between seasons and unpredictably from year to year. Most of the rain comes in the so-called summer monsoon from June to November. The winter months, from December to May, are relatively dry, limiting the growing season for crops unless one can store rain falling in the rainy season—which the Khmer did do, as we shall see. As for variation between years, annual rainfall can be as low as 38 inches, or as high as 91 inches. That would expose Angkor’s inhabitants to the opposite risks of crop failures from droughts or from flooding, unless they had systems for storing rain in wet years to release in dry years and for controlling and quickly disposing of rain runoff during flood seasons. As we shall see, the Khmer water management system also coped with those problems for many centuries, until it finally became overwhelmed by extreme weather swings between severe droughts and severe floods.

  To the south of Angkor are low mountains rising from the coast of the Gulf of Thailand. As a result, the Khmer Empire was oriented inland rather than toward maritime trade, and only in 1960 did Cambodia finally complete its first coastal seaport accessible to deep-draft oceangoing ships. To the north of Angkor at a distance of about 12 miles are the Kulen Hills, so steep that their slopes are prone to massive soil erosion if they become deforested. (That also emerged as a problem for the Khmer Empire.) From the Kulen Hills southward beyond Angkor, the terrain is extremely flat, with an average slope of only 0.1%. That created big problems of controlling water flows across the plains for the Khmer engineers of Angkor. It also created big problems of sanitation, because water flows across those flat plains were so slow. Rivers and channels in the plains supplied water for drinking, cooking, and bathing, but also functioned as the area’s sewers. A Chinese visitor to Angkor at its height commented on the frequency of cases of dysentery, which (the visitor wrote) proved fatal for 90% of the victims.

  An outstanding feature of the Khmer heartland, and probably the main reason for the location of the Khmer capital at Angkor, is Southeast Asia’s largest lake, called the Tonle Sap (Lake Tonle), which constitutes an expansion of the Tonle River, one of the four branches of the Mekong River. In the dry season the shallow lake shrinks to an area of 1,000 square miles. But in the wet season the volume of water coming down the Mekong’s main branch is so large that the dry-season flow of water from the lake down the Tonle River reverses, and floodwaters back up the river into the lake, whose area quadruples to 4,000 square miles. That means 3,000 square miles of floodplain that is seasonally watered by natural flooding and is ideal for growing rice.

  A second benefit of Lake Tonle for nearby Angkor’s inhabitants was as a transport artery to the Mekong River and the sea. The remaining advantage was the lake’s high biological productivity, supporting per cubic yard the greatest concentration of freshwater fish in the world, thanks to the sediments carried into the lake each year with the Mekong River floods. An early French visitor to the lake wrote, “The fish in it are so incredibly abundant that when the water is high they are actually crushed under the boats, and the play of oars is frequently impeded by them.” The lake accounts for most of Cambodia’s fisheries today, supplies most of the dietary protein of Cambodians, and is responsible for their enjoying one of the world’s highest levels of fish consumption.

  While rice was the food staple of the Khmer in the past as it is of modern Cambodians, much of the Cambodian plain rates as land of only medium to poor quality for growing rice. The soils are mostly sandy and low in nutrient content. Of the three main methods for growing rice in Cambodia, one, practiced especially in hilly uplands, is swidden, or slash-and-burn, agriculture, wholly dependent on rain falling on the fields for watering the crop. The second and most extensive method, but still not especially productive by Chinese and Japanese standards, is rice paddies on flat terrain flooded by rain. The most productive method, which yielded most of the rice consumed by the ancient Khmer, is termed flood-retreat farming: rice is planted in fields into which water stored in upstream impoundments is released.

  Thus, Angkor’s environment offered some advantages—especially those associated with the lake, and with the large area of flat plain available in the Lower Mekong Basin. But it also posed problems. The Khmer solved those problems brilliantly for many centuries, thereby succeeding in establishing a g
reat city and empire, but eventually became defeated by the problems.

  Who are the Khmer, and how did their empire arise? Today the Khmer constitute 90% of Cambodia’s population, and they already dominated the area of Angkor at least 1,400 years ago, to judge from preserved Khmer inscriptions on stone. The Khmer language belongs to the Austroasiatic language family, consisting of about 150 languages spoken in scattered areas from India to North Vietnam and the Malay Peninsula and mostly surrounded by speakers of other language families (especially the Sino-Tibetan and Tai-Kadai families). That fragmented distribution suggests that the latter two families have been encroaching on Austroasiatic lands, and indeed we know that the Thais and Vietnamese have been expanding in historic times. The only other Austroasiatic language besides Khmer likely to be familiar to most readers of this book is the distantly related Vietnamese language, which has become much more heavily modified through contact with Chinese (e.g., in becoming a tonal language) than has the Khmer language.

  Until as recently as 5,000 years ago, all peoples of tropical Southeast Asia were stone tool-using hunter-gatherers, as was formerly true of everybody everywhere in the world until the origins of agriculture. Rice farming reached Cambodia from southern China by 2000 B.C., and the subsequent arrival of efficient iron tools around 500 B.C. fueled increased food production and a population explosion. By around A.D. 200, archaeological excavations in Cambodia revealed the existence of modest-sized towns and small kingdoms. From A.D. 245 onward, Chinese imperial records describe a cunning, malicious people of a land named “Funan” which evidently lies in modern Cambodia, which sent trade missions or tribute to China, and whose kings rode on the backs of elephants. Despite those contacts with China, Cambodia became much more strongly influenced by contacts with India, whence (beginning by around A.D. 300) arrived the Hindu and Buddhist religions, writing derived from South India’s Brahmi script, and use of the Sanskrit language for religious texts. The first inscription in the Khmer language itself dates to A.D. 611.