The Threat of Agrarian Collapse

 Collapse: How Societies Choose to Fail or Succeed -- By Jared Diamond (New York: Viking, 2005)

If you thought human society risked collapse because of global warming, exhaustion of fossil fuels, and overpopulation, UCLA geographer Jared Diamond has a whole new list of things to worry about. Diamond is the author of the insightful Guns, Germs, and Steel, which theorized a nonracial explanation for European supremacy over the New World and Africa based on the availability of domesticable animals and grains and a greater exposure to and hence immunity to common diseases. In Collapse Diamond traces in exhaustive detail the ecological disasters that destroyed four ancient and medieval societies, and points to parallels in our own time as warning signs.Diamond's examples are comparatively small, isolated units living in fragile, unforgiving landscapes. The advantage of concentrating on such otherwise marginal peoples is that by their isolation it is easier to piece together the factors that led to their destruction. Diamond chooses the Polynesian people of Easter Island off the coast of Chile, the vanished Anasazi of the deserts of northeastern Arizona, northwestern New Mexico, southeastern Utah and southwestern Colorado; the Maya of the Yucatan Peninsula; and the Norse colonies in western Greenland.

While there are important differences in the factors that led to social failure between these examples, a common thread is deforestation, leading to a loss of building materials and fuel; extermination through over-hunting of local animals and birds used for food; and erosion and salinization of croplands as a consequence of the loss of woodland cover on hillsides.

A cardinal risk factor unearthed in Diamond's study is cultural expansion into territories that appear to be the same as the homeland but in fact have difficult to detect but crucial differences. Dust carried ashore by the Southeast Asian monsoons provides a natural fertilizer that renews croplands and encourages rapid growth of coconut palms and other trees on many South Pacific islands.

As Polynesian colonies spread further east across the Pacific toward South America, Diamond says, they eventually outran the monsoon effect. At Easter Island, located 2,200 miles west of continental Chile, the lack of monsoon-carried dust meant the land was poor and trees grew far more slowly than in the western Pacific. Harvesting wood at the same rate as in the monsoon area eventually denuded the island's forests with disastrous consequences. Colonized around 900 AD, there may have been 15,000 inhabitants at the height in the thirteenth century. By the time European ships arrived in 1722 there were 2,000 left, and these were quickly decimated by slave traders and small pox.

Searches through garbage middens reveal that for the early inhabitants dolphin was a major food source, with fish far scarcer than in most Polynesian societies. This was apparently because of the rocky coast that left few places to fish. The dolphins were caught at sea from ocean-going canoes. Over time the big trees used to make such canoes were all cut down. When the trees were gone, the diet changed as well.

"Porpoises, and open-ocean fish like tuna, virtually disappeared from the islanders' diet. . . . Land birds disappeared completely from the diet, for the simple reason that every species became extinct from some combination of overhunting, deforestation, and predation by rats" (p. 106).

With the trees, palm nuts also disappeared, removing another important food source. The latest carbon date for a palm nut shell found on the island is 1500. The population crashed in the century that followed. Crops also failed. "Deforestation led locally to soil erosion by rain and wind, as shown by huge increases in the quantities of soil-derived metal ions" (p. 108).

For the Norse colony in Greenland, again the land looked a lot like home, in this case Norway, but in fact the soil was far poorer. The colonists tried to replicate their home ecology, raising cattle and sheep, and growing crops. Founded in 984, the colony, based in two fjords on the southwest coast, lasted some 450 years. They prospered until the Little Ice Age set in after 1300. They then faced competition from the invading Inuit, saw crop failures from the deepening cold and the thin topsoil, and made fatal cultural mistakes, the most important of which was relying on sheep and cattle that could no longer be fed when the hay harvests failed, rather than on seal and fish as the Inuit did.

What bearing do these isolated local tragedies have for our globalized world? Diamond makes an analogy with the two Norse colonies in Greenland. In fact, he says, the more southerly one had a chance to survive, or at least its largest farms did, with great barns where they housed their cattle in the winter. The outlying areas evacuated and migrated to the better-off places in hopes of staving off the disaster. They succeeded only in swamping the life boat and all drowned together.

Diamond sees the globalized world of today as more subject to ecological shocks than the relatively self-isolated nation states of a century ago. He has been criticized for not having an economist's tools to weigh more accurately the growth of wealth as a balance against ecological costs. Cambridge economist Partha Dasgupta in a review last year in the London Review of Books pointed out that deforestation in Britain in the nineteenth century spurred that country to switch to coal and become the leader of the Industrial Revolution while well-forested France fell behind. Dasgupta asks "how should we recognise the trade-offs between a society's present and future needs for goods and services?" and scores Diamond for lacking a clear concept of sustainable development.

That is an issue beyond my qualifications to evaluate. There is, however, one striking point that Diamond makes. There is in the world today a world market in food grains. The principal suppliers of this market for some years have been the United States, Canada, and Australia. One ominous sign has been China's transition from grain self-sufficiency to become a major grain importer.

As the world's most populous country, China's relations to the world grain market can have an enormous impact. Historically China with its intensive, irrigated garden farming and extremely limited arable land has lived far closer to the edge than the countries of Western Europe and North America with their large tracts of rainfall farming.

Population growth, even with the government's one-child policy, is having powerful impacts on the country's capacity to feed itself. Diamond writes:

"By world standards, China is poor in fresh water, with a quantity per person only one-quarter of the world average value. . . . Of the water required for cities and for irrigation, two-thirds depends on groundwater pumped from wells tapping aquifers. However, these aquifers are becoming depleted, permitting seawater to enter them in most coastal areas, and causing land to sink under some cities as the aquifers are becoming emptied. . . . China's soil problems start with its being one of the world's countries most severely damaged by erosion, now affecting 19% of its land area and resulting in soil loss at 5 billion tons per year. Erosion is especially devastating on the Loess Plateau . . . and increasingly on the Yangtze River, whose sediment discharge from erosion exceeds the combined discharges of the Nile and Amazon. . . .

"Soil quality and fertility as well as soil quantity have declined, partly because of long-term fertilizer use plus pesticide-related drastic declines in soil-renewing earthworms, thereby causing a 50% decrease in the area of cropland considered to be of high quality. Salinization . . . has affected 9% of China's lands, mainly due to poor design and management of irrigation systems in dry areas. . . . Desertification, due to overgrazing and land reclamation for agriculture, has affected more than one-quarter of China, destroying about 15% of North China's area remaining for agriculture and pastoralism within the last decade." (pp. 364-65)

The World Watch Institute in a January 11, 2006, report said that China in 2005 consumed 32 percent of the rice output of the world, and that "If Chinese per-capita grain consumption were to double to roughly European levels, China alone would require the equivalent of nearly 40 percent of today's global grain harvest."

At the same time, Jared Diamond reports, Australia, one of the current pillars of world grain exports, is faced with its own erosion and salinization problems that are likely to move it from an exporter to an importer in the next decade. This spells a global food supply in which a single bad year will mean large scale famine in many countries.

At root the world as a whole is confronting a growing pressure on mostly limited resources, including agrarian ones that are most often overlooked, from both a growth in population and a simultaneous growth in per capita use of resources.

Skeptics can quibble, but their counter arguments have to rest on two risky assumptions: that new technology fixes will turn up in time to solve the growing food and energy problems, as the turn to coal did for the British 200 years ago, and that governments will be brave and energetic enough to confront their populations with unpopular demands to reduce population growth and conserve resources. Not to mention the opposition such measures face now from Muslim forces in the Middle East and Indonesia, and fundamentalist Christian forces that wield enormous power here in the United States, who oppose such measures on the ground that God will take care of it or take his followers up to heaven soon where it won't matter.

Jared Diamond himself is not a pessimist, or at least so he says. He points to the amazingly effective forest management efforts of the Tokugawa Shogunate in Japan after 1600 that protected the country's forests, even to the point of inventorying individual trees. And no doubt there is growing awareness of the rising risks and public and private projects to conserve and to find alternatives. We will see.