Collapse: How Societies Choose to Fail or Survive

by Jared Diamond

Thus, we have known for a long time that mine wastes can be sequestered so as to minimize problems; some new mines around the world now do so with state-of-the-art technology, while others continue to ignore the problem. In the U.S. today, a company opening a new mine is required by law to buy a bond by which a separate bond-holding company pledges to pay for the mine’s cleanup costs in case the mining company itself goes bankrupt.

A sign posted over the toilet of one Montanan friend of mine reads, “Do not flush. Be like the mining industry and let someone else clean up your waste!”

Here is how a saline seep arises. Eastern Montana has lots of water-soluble salts (especially sodium, calcium, and magnesium sulfates) present as components of the rocks and soils themselves, and also trapped in marine deposits (because much of the region used to be ocean). Below the soil zone is a layer of bedrock (shale, sandstone, or coal) that has low permeability to water. In dry eastern Montana environments covered with native vegetation, almost all rain that falls is promptly taken up by the vegetation’s roots and transpired back into the atmosphere, leaving the soil below the root layer dry. However, when a farmer clears the native vegetation to practice crop-and-fallow agriculture, in which an annual crop like wheat is grown during one year and the land is left fallow the next year, there are no plant roots to take up rainwater falling in the fallow year. That rainwater accumulates in the soil, waterlogs it below the root layer, and dissolves salts that then rise into the root zone as the water table rises. Because of the impermeable underlying bedrock, the salty water doesn’t drain deeply into the ground but emerges somewhere downhill nearby as a saline seep. The result is that crops grow more poorly or not at all, both in the uphill area where the problem arises and in the downhill area where the seep emerges.

Rock garden or lithic mulch agriculture was invented independently by farmers in many other dry parts of the world, such as Israel’s Negev desert, southwestern U.S. deserts, and dry parts of Peru, China, Roman Italy, and Maori New Zealand. Rocks make the soil moister by covering it, reducing evaporative water loss due to sun and wind, and replacing a hard surface crust of soil that would otherwise promote rain runoff. Rocks damp out diurnal fluctuations in soil temperature by absorbing solar heat during the day and releasing it at night; they protect soil against being eroded by splashing rain droplets; dark rocks on lighter soil warm up the soil by absorbing more solar heat; and rocks may also serve as slow-time-release fertilizer pills (analogous to the slow-time-release vitamin pills that some of us take with breakfast), by containing needed minerals that gradually become leached out into the soil.

Knowing what we do about Easter Island technology, it seems impossible that the islanders could ever have transported and erected it, and we have to wonder what megalomania possessed its carvers.

In place of their former sources of wild meat, islanders turned to the largest hitherto unused source available to them: humans, whose bones became common not only in proper burials but also (cracked to extract the marrow) in late Easter Island garbage heaps.

What had failed, in the twilight of Easter’s Polynesian society, was not only the old political ideology but also the old religion, which became discarded along with the chiefs’ power. Oral traditions record that the last ahu and moai were erected around 1620, and that Paro (the tallest statue) was among the last.

Easter Islanders’ toppling of their ancestral moai reminds me of Russians and Romanians toppling the statues of Stalin and Ceauşescu when the Communist governments of those countries collapsed.

Again as on other Pacific islands, “black-birding,” the kidnapping of islanders to become laborers, began on Easter around 1805 and climaxed in 1862–63, the grimmest year of Easter’s history, when two dozen Peruvian ships abducted about 1,500 people (half of the surviving population) and sold them at auction to work in Peru’s guano mines and other menial jobs. Most of those kidnapped died in captivity. Under international pressure, Peru repatriated a dozen surviving captives, who brought another smallpox epidemic to the island. Catholic missionaries took up residence in 1864. By 1872 there were only 111 islanders left on Easter.

One of them, Pitcairn Island, is famous as the “uninhabited” island to which the mutineers from the H.M.S. Bounty fled in 1790. They chose Pitcairn because it was indeed uninhabited at that time, remote, and hence offered a hiding place from the vengeful British navy searching for them. But the mutineers did find temple platforms, petroglyphs, and stone tools giving mute evidence that Pitcairn had formerly supported an ancient Polynesian population.

The journey from Mangareva to Henderson would take four or five days by Polynesian sailing canoes; from Pitcairn to Henderson, about one day. My own perspective on sea journeys in Pacific native canoes is based on much briefer voyages, which left me constantly terrified of the canoe’s capsizing or breaking up and in one case nearly cost me my life. That makes the thought of a several-day canoe voyage across open ocean intolerable to me, something that only a desperate need to save my life could induce me to undertake. But to modern Pacific seafaring peoples, who sail their canoes five days just to buy cigarettes, the journeys are part of normal life.

With too many people and too little food, Mangareva society slid into a nightmare of civil war and chronic hunger, whose consequences are recalled in detail by modern islanders. For protein, people turned to cannibalism, in the form not only of eating freshly dead people but also of digging up and eating buried corpses. Chronic fighting broke out over the precious remaining cultivable land; the winning side redistributed the land of the losers. Instead of an orderly political system based on hereditary chiefs, non-hereditary warriors took over. The thought of Lilliputian military dictatorships on eastern and western Mangareva, battling for control of an island only five miles long, could seem funny if it were not so tragic.

Chaco society turned into a mini-empire, divided between a well-fed elite living in luxury and a less well-fed peasantry doing the work and raising the food. The road system and the regional extent of standardized architecture testify to the large size of the area over which the economy and culture of Chaco and its outliers were regionally integrated.

While everyone acknowledges that cannibalism may be practiced in emergencies by desperate people, such as the Donner Party trapped by snow at Donner Pass en route to California in the winter of 1846–47, or by starving Russians during the siege of Leningrad during World War II, the existence of non-emergency cannibalism is controversial. In fact, it was reported in hundreds of non-European societies at the times when they were first contacted by Europeans within recent centuries. The practice took two forms: eating either the bodies of enemies killed in war, or else eating one’s own relatives who had died of natural causes. New Guineans with whom I have worked over the past 40 years have matter-of-factly described their cannibalistic practices, have expressed disgust at our own Western burial customs of burying relatives without doing them the honor of eating them, and one of my best New Guinean workers quit his job with me in 1965 in order to partake in the consumption of his recently deceased prospective son-in-law.

Especially important, both for bad and for good, was the bishop Diego de Landa, who resided in the Yucatán Peninsula for most of the years from 1549 to 1578. On the one hand, in one of history’s worst acts of cultural vandalism, he burned all Maya manuscripts that he could locate in his effort to eliminate “paganism,” so that only four survive today. On the other hand, he wrote a detailed account of Maya society, and he obtained from an informant a garbled explanation of Maya writing that eventually, nearly four centuries later, turned out to offer clues to its decipherment.

We are accustomed to thinking of military success as determined by quality of weaponry, rather than by food supply. But a clear example of how improvements in food supply may decisively increase military success comes from the history of Maori New Zealand. The Maori are the Polynesian people who were the first to settle New Zealand. Traditionally, they fought frequent fierce wars against each other, but only against closely neighboring tribes. Those wars were limited by the modest productivity of their agriculture, whose staple crop was sweet potatoes. It was not possible to grow enough sweet potatoes to feed an army in the field for a long time or on distant marches. When Europeans arrived in New Zealand, they brought potatoes, which beginning around 1815 considerably increased Maori crop yields. Maori could now grow enough food to supply armies in the field for many weeks. The result was a 15-year period in Maori history, from 1818 until 1833, when Maori tribes that had acquired potatoes and guns from the English sent armies out on raids to attack tribes hundreds of miles away that had not yet acquired potatoes and guns.

The Christian churches that were created in Iceland and Greenland after A.D. 1000 were not independent entities owning their own land and buildings, as are modern churches. Instead, they were built and owned by a leading local farmer/chief on his own land, and the farmer was entitled to a share of the taxes collected as tithes by that church from other local people. It was as if the chief negotiated a franchise agreement with McDonald’s, under which he was granted a local monopoly by McDonald’s, erected a church building and supplied merchandise according to uniform McDonald’s standards, and kept a part of the proceeds for himself while sending the rest of the proceeds to central management—in this case, the pope in Rome via the archbishop in Nidaros (modern Trondheim).

In 1607 a Danish-Norwegian expedition set out specifically to visit Eastern Settlement, but was deceived by the name into supposing that it lay on Greenland’s east coast and hence found no evidence of the Norse. From then on, throughout the 17th century, more Danish-Norwegian expeditions and Dutch and English whalers stopped in Greenland and kidnapped more Inuit, who (incomprehensibly to us today) were assumed to be nothing more than descendants of blue-eyed blond-haired Vikings, despite their completely different physical appearance and language.

The species is fast-growing. Its wood is excellent for timber and fuel. Its root nodules that fix nitrogen, and its copious leaf-fall, add both nitrogen and carbon to the soil. Hence casuarinas grown interspersed in active gardens increase the soil’s fertility, while casuarinas grown in abandoned gardens shorten the length of time that the site must be left fallow to recover its fertility before a new crop can be planted. The roots hold soil on steep slopes and thereby reduce erosion. New Guinea farmers claim that the trees somehow reduce garden infestation with a taro beetle, and experience suggests that they are right about that claim as they are about many others, though agronomists still haven’t figured out the basis of the tree’s claimed anti-beetle potency.

Within each village, instead of hereditary leaders or chiefs, there were just individuals, called “big-men,” who by force of personality were more influential than other individuals but still lived in a hut like everybody else’s and tilled a garden like anybody else’s. Decisions were (and often still are today) reached by means of everybody in the village sitting down together and talking, and talking, and talking. The big-men couldn’t give orders, and they might or might not succeed in persuading others to adopt their proposals. To outsiders today (including not just me but often New Guinea government officials themselves), that bottom-up approach to decision-making can be frustrating, because you can’t go to some designated village leader and get a quick answer to your request; you have to have the patience to endure talk-talk-talk for hours or days with every villager who has some opinion to offer.

At the first stage, the shogun, who directly controlled about a quarter of Japan’s forests, designated a senior magistrate in the finance ministry to be responsible for his forests, and almost all of the 250 daimyo followed suit by each appointing his own forest magistrate for his land. Those magistrates closed off logged lands to permit forest regeneration, issued licenses specifying the peasants’ rights to cut timber or graze animals on government forest land, and banned the practice of burning forests to clear land for shifting cultivation. In those forests controlled not by the shogun or daimyo but by villages, the village headman managed the forest as common property for the use of all villagers, developed rules about the harvesting of forest products, forbade “foreign” peasants of other villages to use his own village’s forest, and hired armed guards to enforce all these rules.

In 1668 the shogun went on to ban use of cypress, sugi, or any other good tree for public signboards, and 38 years later large pines were removed from the list of trees approved for making New Year decorations.