|The massing of humans into cities is all too similar to the way crowded cancer cells harden into tumors. Whereas normal cells in a tissue culture stop reproducing when they come in contact with other cells, cancer cells continue to divide and pile up on top of one another, forming clumps. Normal cells display contact inhibition, growing only to the limits of their defined space and then stopping. Cancer cells never know when to quit.
Likewise, human populations grow even under extremely crowded conditions. The very essence of civilization is the concentration of people in cities. As scattered farming villages evolved into towns, and some towns became trading, manufacturing, ceremonial and administrative centers, the city was born. Fed by grain grown in the provinces and served by slaves seized there, the administrative centers of empires grew large; Rome may have reached one million people at its height in 100 C.E. Yet not until industrialization and the extensive exploitation of distant resources after 1800 did cities really begin getting out of hand, and in 1900, still only one in ten people lived in cities. Half will in 2000, with 20 metropolitan areas expected to have 10 million or more people each.
The propensity of modern cities to spread out over the countryside–absorbing villages, destroying farm fields, filling in open land, and creating vast new agglomerations–was noted early in this century by the Scottish garden-city planner Patrick Geddes. Geddes (1915) identified half a dozen such “conurbations” in the making in Britain, and he foresaw the approach of a 500-mile megalopolis along the northern Atlantic seaboard in the United States. Geddes compared urban sprawl to an amoeba, but it fell to his American protege Lewis Mumford to liken disorderly, shapeless, uncoordinated urban expansion to a malignant tumor, observing that “the city continues to grow inorganically, indeed cancerously, by a continuous breaking down of old tissues, and an overgrowth of formless new tissue” (Mumford 1961, p. 543).
A malignant tumor develops its own blood vessels as it grows. Similarly, cities vascularize with aqueducts, electric power lines, highways, railroads, canals and other conduits. A tumor uses its circulation network to pirate nutrients from the body. Similarly, cities parasitically tap the countryside and beyond to bring in food, fuel, water, and other supplies. However, just as a tumor eventually outgrows its blood supply, causing a part of it, often at the center, to die, inner city neighborhoods and even older suburbs often atrophy. Alan Gregg (1955) noted this parallel 40 years ago, observing “how nearly the slums of our great cities resemble the necrosis of tumors.”
Humans are increasingly concentrated along seacoasts. Sixty percent of the world’s people now live within 100 kilometers of a seacoast. In Australia, one of the world’s most highly urbanized nations, nine of every ten people live along the coast. The boom in international trade, from which coastal areas receive a disproportionate share of the benefits, helps explain the worldwide trend; but the pattern goes back thousands of years and parallels yet another carcinogenic process: metastasis.
In metastasis, a tumor sheds cancer cells that then migrate to distant sites of the body and set up secondary growths. The medium for the migration of the cells is the blood and lymphatic systems. In the ancient world of the Mediterranean, another fluid–water–facilitated the migration of people and goods. The Phoenicians, Greeks, Carthagenians and Romans all took advantage of the relative ease of travel and transport by water to establish colonies all around the Mediterranean. At the height of the Roman Empire, no fewer than 500 settlements flourished along the African coast from Morocco to Egypt.
Just as secondary tumors in the human body destroy the tissues and organs they invade, colonizers of the ancient Mediterranean devastated the fertile but fragile ecosystems of the coastal regions they colonized. They logged coastal forests for ship timbers and building materials, to provide charcoal to fire bricks and pottery and smelt mineral ores, and to create farm fields and pastures. Overcropping, fires, sheep and goats prevented regeneration. Intense winter rains washed the thin, easily eroded soil down hillsides into coastal plains to smother farm fields, choke the mouths of rivers, create malarial marshes, bury port cities and strand many of them miles from the sea. The slopes, left barren, have not recovered to this day.
The voraciousness of secondary tumors as they invade and consume tissues and organs has its counterpart in the orgies of destruction that states and especially empires have engaged in for 5000 years. In many cases, the destruction has exceeded what was in the destroyer’s own self-interest. Many invaders routinely obliterated the cities they conquered, massacred their inhabitants, and destroyed their fields and flocks instead of just taking them over. Carpet bombing of cities and the mass slaughter of their civilian noncombatant populations during World War II constitute the modern equivalent. Ancient Romans ransacked their empire for bears, lions, leopards, elephants, rhinos, hippos and other live animals to be tormented and killed in public arenas until there were no more to be found. European invaders of North America and Siberia did in the fur trade from which they so hugely profited by the self-defeating overkill of fur-bearing animals.
Human destruction of ecosystems has increased relentlessly since industrialization. The annihilation of 60 million bison on the North American Great Plains was made possible by the intrusion of railroads and the invention of the repeating rifle. The reckless exploitation of whales was speeded by the invention of the explosive harpoon, cannon-winch and engine-driven ship. Enormous nets towed by today’s factory trawlers permit oceans to be strip-mined for fish–and any other creature unlucky enough to become ensnared in these curtains of death. Tractors and other modern farm machinery alternately compact and pulverize topsoil, increasing its vulnerability to erosive winds and rains. Chain saws and bulldozers level forests faster than axes and hand saws ever could. Dynamite and drag line excavators permit strip mining on a scale hitherto unimaginable, decapitating mountains, turning landscapes into moon craters, and rendering islands such as phosphate-rich Nauru in the South Pacific all but uninhabitable. Boring holes in the earth to get at minerals, of course, resembles the way cancer bores holes in muscle and bone. As Peter Russell (1983, p.33) has observed, “Technological civilization really does look like a rampant malignant growth blindly devouring its own ancestral host in a selfish act of consumption.”
Just as a fast-growing tumor steals nutrients from healthy parts of the body to meet its high energy demands, industrial civilization usurps the resources of healthy ecosystems that their natural plant and animal inhabitants depend on for survival. In 1850, humans and their livestock accounted for 5 percent of the total weight of all terrestrial animal life. Today, that portion exceeds 20 percent, and by the year 2030 it could reach 40 percent (Westing 1990, pp. 110-111).
“Never before in the history of the earth has a single species been so widely distributed and monopolized such a large fraction of the energetic resources. An ever diminishing remainder of these limited resources is now being divided among millions of other species. The consequences are predictable: contraction of geographic ranges, reduction of population sizes, and increased probability of extinction for most wild species; expansion of ranges and increased populations of the few species that benefit from human activity; and loss of biological diversity at all scales from local to global” (Brown and Maurer 1989).
Decline in diversity is common to both cancer and civilization. In both cases, heterogeneity gives way to homogeneity, complexity to simplification. Malignant cells fail to develop into specialized cells of the tissues from which they derive. Instead, “undifferentiated, highly malignant cells tend to resemble one another and fetal tissues more than their adult normal counterpart cells” (Ruddon 1987, p.230).
De-differentiation in human societies is at least as old as agriculture and animal husbandry. Farmers have been replacing diverse species of native plants with pure stands of domesticated crops for thousands of years. Instead of the thousands of kinds of plants that pre-agricultural peoples gathered for food, just seven staples–wheat, rice, maize, potatoes, barley, sweet potato and cassava–now supply three-quarters of the caloric content of all the world’s food crops. The world’s astonishing abundance and variety of wildlife is going fast, with many species soon to be seen only in zoos and game parks, their places taken by cattle, sheep, goats, pigs and other domesticated livestock.
Despite their value in providing wildlife habitat, modulating flood waters and filtering out pollutants, more than half of the world’s swamps, marshes, bogs, seasonal flood plains and other wetlands have been drained, dredged, filled in, built on or otherwise destroyed. Temperate forests dominated by trees of many species and of all ages are giving way to single species, same-aged conifer plantations supporting far fewer birds and other wildlife. And the tropical forests that harbor more than half of all species on Earth are being mowed down faster than their bewildering biodiversity can be identified, leading some experts to warn that we are causing the greatest mass extinction since the disappearance of the dinosaurs 65 million years ago.
The tendency of civilizations to homogenize and impoverish ecosystems is nowhere clearer than in urban areas. Major cities are becoming indistinguishable from one another in appearance and undifferentiated in function. Central business districts so resemble one another that travelers can be forgiven for forgetting whether they are in Boston, Brussels or Bombay. Shanty cities in poor countries look alike, as do suburbs in rich countries.
As Lewis Mumford pointed out more than 30 years ago, the archetypal suburban refuge in the United States consists of “a multitude of uniform, unidentifiable houses, lined up inflexibly, at uniform distances, on uniform roads, in a treeless communal waste, inhabited by people of the same class, the same income, the same age group, witnessing the same television performances, eating the same tasteless pre-fabricated foods, from the same freezers, conforming in every outward and inward respect to a common mold, manufactured in the central metropolis. Thus the ultimate effect of the suburban escape in our time is, ironically, a low-grade uniform environment from which escape is impossible” (Mumford 1961, p.486).
Globalization of the economy is enclosing the entire world in a single market for machine-made goods that are increasingly standardized whatever their country of origin. Western material values and capitalist commodity culture, led by American television, movies, music, street fashions and fast food, are dominant internationally. Local and regional individuality, along with indigenous cultures, languages and world views, are fading fast.
The decline of natural and cultural diversity is as threatening to the planet as undifferentiated cells are to the cancer patient. Whereas a well-differentiated prostate cancer tends to grow slowly, remain localized and cause no symptoms, a poorly differentiated one often spreads aggressively. Similarly, traditional farmers who keep weeds, pests and plant diseases in check by rotating crops, fertilizing naturally, and maintaining the tilth of the soil don’t threaten Earth’s health the way single-crop plantations relying on pesticides, synthetic fertilizers and heavy machinery do. Unfortunately, monocultural agriculture is becoming the norm on every continent.
Hemorrhaging is still another symptom of the carcinogenic process. The first sign of cancer is often spontaneous bleeding from a body orifice, discharge from a nipple, or an oozing sore. Vomiting can warn of a brain tumor or leukemia. Signs that Earth, too, has cancer abound. Cities vomit human sewage and industrial wastes into adjacent waterways. Mines and slag heaps ooze mercury, arsenic, cyanide and sulfuric acid. Wells gush, pipelines leak and tankers spill oil. Farm fields discharge topsoil, fertilizers, pesticides and salts to silt up and poison rivers and estuaries. Cattle feedlots add manure. Most serious of all, deforested, eroded hillsides hemorrhage floods of mud.
Fever is another symptom of cancer in both humans and the planet. Cancer patients become fevered because of increased susceptibility to infection caused by a depressed immune system. Chemotherapy and irradiation can also cause fever, as can temperature-elevating substances released by a malignant tumor. Global warming is the planetary counterpart. Waste products released by industry and motor vehicles, deforestation and other feverish human activities pump inordinate quantities of carbon dioxide, nitrous oxide, methane, chlorofluorocarbons and other greenhouse gases into the atmosphere where they trap heat and raise temperatures.
Wasting, or cachexia, is still another sign of advanced cancer. A cancer patient becomes fatigued and weak, losing both appetite and weight as the tumor releases toxic hormones and makes metabolic demands on the body. “Many cancer patients die not of cancer itself, but of progressive malnutrition” (Rosenbaum 1988, p.264). The planetary counterpart includes loss of forests, fisheries, biodiversity, soil, groundwater and biomass.
It’s not in a tumor’s self-interest to steal nutrients to the point where the host starves to death, for this kills the tumor as well. Yet tumors commonly continue growing until the victim wastes away. A malignant tumor usually goes undetected until the number of cells in it has doubled at least 30 times from a single cell. The number of humans on Earth has already doubled 32 times, reaching that mark in 1978 when world population passed 4.3 billion. Thirty-seven to 40 doublings, at which point a tumor weighs about one kilogram, are usually fatal (Tannock 1992, pp. 157, 175).
Like a smoker who exaggerates the pain of withdrawal and persists because the carcinogenic consequences of his bad habit don’t show up for 20 or 30 years, governments generally avoid the painful adjustments needed to prevent social, economic and environmental disasters in the making. “Governments with limited tenure, in the developing as well as in the developed countries, generally respond to immediate political priorities; they tend to defer addressing the longer term issues, preferring instead to provide subsidies, initiate studies, or make piecemeal modifications of policy” (Hillel 1991, p. 273). So it usually takes a crisis, often a catastrophe, before even the most commonsensical action is taken–and then it is often too late to avoid irreversible ecological damage.
Is the prognosis for the planet as grim as it is for a patient with advanced cancer? Or will infinitely clever but infrequently wise Homo sapiens alter geocidal behaviors in time to avoid global ruin? Even the most pessimistic doomsayers concede that humans have the capacity to arrest Gaia’s deteriorating condition. Cancer cells can’t think, but humans can. Cancer cells can’t know the full extent of the harm they’re doing to the organism of which they are a part, whereas humans have the capacity for planetary awareness. Cancer cells can’t consciously modify their behavior to spare their host’s life and prolong their own, whereas humans can adjust, adapt, innovate, pull back, change course.
Gaia’s future, and humans’ with it, depends on their doing so.
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A. Kent MacDougall (911 Oxford St., Berkeley CA 94707) is professor emeritus of journalism at the University of California, Berkeley. He completed his 25-year newspaper reporting career in 1987 with a 24,000-word series of articles for the Los Angeles Times on deforestation around the world and through the ages. The series won the Forest History Society’s John M. Collier Award for Forest History Journalism.