Ice age politics

Halfway along wilshire Boulevard, between Beverly Hills and the Wilshire country club, there is a tiny park called Hancock park with a little pond in it. The pond looks quaint enough, until you notice the sheen on the surface and the viscous bubbles that occasionally break that sheen. It is a natural seepage of oil, known as the La Brea Tar pit. A museum stands in the park and in it are the bones of all the animals that have been dredged from the swamps that once surrounded the site. There are wild camels, wild horses, mastodons, sabre-toothed tigers, wolves, lions and many more such skeletons. The animals came year after year, attracted by the "water" and became mired in the tar.

All the creatures that died in the La Brea Tar pits are now extinct. Even if there were no Los Angeles, they would not come back. Yet once upon a time the area was as rich in big mammals as the Serengeti plain. What happened to those animals? This might seem like an innocent empirical question for objective scientists. But it is in fact an increasingly fraught question-one that has highly political overtones.

First, the facts. Archaeologists agree that there occurred-between 12,000 and 8,000 years ago-a holocaust known as the Pleistocene overkill, which killed almost all the large mammals on the two American continents. Familiar creatures-wild camels, wild horses, giant beavers, giant capybaras, several kinds of deer, antelope, bear and llama-disappeared. So did the beasts that caught our imaginations in school: sabre-toothed and scimitar-toothed tigers, short-faced bears, mammoths, giant sloths. So did things we hardly know how to pronounce, and which left not even distant relatives for us to see: glyptodonts, gomphotheres, toxodonts, litopterns. In all, about 75 per cent of all the large mammals of North and South America disappeared.



The long established scientific consensus is that it was all our ancestors' fault, or rather, and this is where things start to get political, the fault of the ancestors of native Americans. They arrived in Alaska across the Bering land bridge tens of thousands of years ago, but were initially prevented from moving farther south by an ice cap stretching from the Yukon to the Rockies. Not until 12,000 years ago did the ice retreat enough to let through a tribe known by the unlikely, Saki-like name of the Clovis people (from one of their sites at Clovis, New Mexico). They descended into what was then a continent of great grassy plains, teeming with large mammals.

Beringia, the land from where this hunting people had come (now lying under the Bering Strait), was similar steppe country. But the hunting life proved a lot easier on the new steppes. For these were not just the first people into America, they were the first apes. Elsewhere, humanity's gradual transformation from an ape with a taste for meat into an effective predator equipped with lethal throwing weapons had taken a million years. Time enough for the instincts of all animals to adapt: an inherent fear of the upright ape, an instinct to flee whenever it came close was the legacy of those million years in the brains of virtually every plains mammal. (To this day, African antelope give people a wider berth than they give lions: lions do not have bows and arrows.)

But the glyptodonts and gomphotheres of America had no such instincts. They were naïvely tame, which would have made their extinction simple. It is striking that all the North American mammals that did survive the overkill were new arrivals from Asia-moose, elk, caribou, bison, antelope-animals that had plenty of experience of humankind.

A glimpse of how tame the American wildlife must have been can be got by visiting parts of the Antarctic, where penguins and seals watch you with liquid, trusting eyes even if you walk up to them and club them to death. The same was still true in the last century when sailors first landed on Pacific islands that had never seen human feet. On Lord Howe island, for example, an island the Polynesians never found, a member of the ship's party left this description: "... A curious brown bird about the size of a Landrail in England walking totally fearless & unconcern'd in all part around us, so we had nothing more to do than to stand still & knock as many as we pleased with a short stick-they never made the least attempt to fly away."

In earlier centuries, as the Polynesians colonised the Pacific, smaller, but even more deadly versions of the Pleistocene overkill happened on every island. On Hawaii, we now know that there were about 100 species of unique birds, many of them large and flightless. Within a short time of the arrival of people in AD 300, no fewer than half of them were extinct. A thousand years later on New Zealand, the first Maoris ate their way through all 12 species of the giant flightless birds called moas (the biggest bird weighing a quarter of a ton).

Yet New Zealand, big as it is, is still an island. To many people it beggars belief that a few thousand hunters, armed with stone tools and bows and arrows could wipe out 40 genera of large mammals on the two great American continents. And in short order, too. The large mammals disappeared around 11,500 years ago-which gives the Clovis people a mere five centuries to do the job from the Yukon to Florida.

To answer this point Paul Martin of the University of Arizona developed a theory called the blitzkrieg hypothesis, which envisages a sort of advancing wave of hunters, shifting a few miles every year on a broad front, but constantly moving southeast because they kept running out of animals to kill. Arrowheads lodged in the ribs of dead mammoths and heaps of butchered bison bones at the base of cliffs where herds were repeatedly stampeded over the edge testify that the Clovis people were no wimps (despite their name).

But hang on a minute. Overkill, blitzkrieg, death stampede-are these not rather outdated stereotypes for native Americans? What happened to the noble savage, who always cares for his prey and uses taboos, rituals and worship to ensure that he lives in harmony with his environment? In certain circles it has become axiomatic to argue that before the white man there was no over-exploitation. "In my opinion," writes the anthropologist Richard Nelson, "the ethnographic record supports the existence of a widespread and well-developed tradition of conservation, land stewardship and religiously based environmental ethics among native Americans." He adds: "We need to rediscover a deep, perhaps spiritually based, affiliation with life."

Feminists, too, have trouble with the blitzkrieg hypothesis. Anna Roosevelt of the University of Illinois, who has recently found bones and tools indicating that people were living off fish and fruit near the mouth of the Amazon almost 11,000 years ago, regards the usual picture of the Clovis people as little more than a boys' fantasy. That the Clovis men were hunters is not in doubt. But what were the Clovettes doing while their men wrestled giant sloths to the ground? Probably making sure there was something a bit more reliable for dinner. These days one talks about gatherer-hunters rather than hunter-gatherers.

Little wonder, therefore, that some scientists express a sort of discomfort with the blitzkrieg hypothesis. It smacks of an outdated, racist and sexist view of humankind. Tribal people are now supposed to be peaceable, spiritual, ecological and wise, not thoughtless extinguishers of wild animals.

This attitude is something of a turnaround, to say the least. When the idea that people might have caused the Pleistocene extinctions was first mooted by Paul Martin in the 1960s, it caught the misanthropic mood of the then emerging environmental movement. But that was when movies were still made with Injuns as bad guys. Times have changed.

And, luckily for the opponents of overkill, there is an even more fashionable villain to hand: climate change. The alternative explanation for the sudden vanishing of the "megafauna" about 11,500 years ago is that the climate grew rapidly warmer. The speed of the change at the end of the last ice age was certainly remarkable. According to one estimate, the temperature in some places rose by as much as seven degrees in 20 years, changing London's climate from Murmansk's to-well, roughly London's.

Big mammals, the argument goes, could not cope. Forests sprang up where there had been steppe. Summers became too hot. Rivers dried up. Migration routes that had once passed through lush grasslands now traversed deserts. Ring any bells? It sounds remarkably like the next century, as portrayed by the Green establishment-people like Peter Melchett and Crispin Tickell. As the theory has gathered strength that human pollution, especially carbon dioxide from the burning of fossil fuels, is causing a rapid increase in global temperatures, so the theory that climate change killed the megafauna has found a new lease of life. The more drastic the effects of climate change are painted by greenhouse theorists, the more archaeologists take note, and vice versa.

The end of the ice age was accompanied by a sharp rise in carbon dioxide, which is one of the reasons why so many scientists argue that carbon dioxide is causing warming today. But at the end of the ice age the carbon dioxide levels seem to have risen after the warming, not before. The truth is that most scientists involved in climate studies now have such large vested interests in global warming that they cannot be trusted to be objective about it. Grants for the study of climate change, ancient and modern, have become much easier to obtain since the Rio de Janeiro conference of 1992 made climate alarmism official UN policy. These grants supply their own momentum to the theory. No sane scientist is going to spend five years on a study of the hypothesis that climate change has drastic ecological effects and come to a negative conclusion-that would consign his work to obscurity and he would be out of a job. Wishful thinking is a powerful motive in science, far more powerful than practitioners like to admit (though this is very different from saying that there is no such thing as an objective fact-the moon is not made of cheese).

However, as far as the ice age extinctions are concerned, the climate change hypothesis is dubious. Global circulation models-the software toys that climatologists use to convince politicians to be scared of global warming-are based partly on guesswork about how climate changed at the end of the ice age. This guesswork is itself partly based on how the vegetation, and the animals that ate it, changed. The disappearance of the mammoth from an area is therefore both proof and premise of the theory of why climate grew warmer there.

This circularity is a weakness. Recently, for example, Russian scientists have made a remarkable reversal of the usual logic in the climate change model. It has long been noticed that the modern taiga (northern forest) and tundra (arctic heath) cannot support herds of large mammals. The trees, mosses, lichens and dwarf shrubs are designed for life on top of permafrost, where nitrogen remains locked up in the ice below and the plants grow slowly and have very little nutritive value.

During the ice age, where there is now taiga and tundra, there was steppe instead-rich, cold grassland. The mammoths whose bodies have been mummified in ice had grass in their stomachs, not moss. To support herds of mammoths, bison and horses, the steppes must have been more fertile than modern tundras. Thus, argue the partisans of climate change, the steppe changed into tundra as the climate grew wetter; the big mammals died out as a result.

Not so, say the Russians. The reason for the fertility of the ice age steppe was the presence of the mammals. Their dung fertilised the grass; their grazing left less dead vegetation to insulate the soil in the spring, which caused the permafrost to thaw more deeply, which released more minerals from the soil, which caused the grass to grow longer, which fed more mammals, which produced more dung and so on in a virtuous circle. Therefore, the change in vegetation was the consequence not the cause of the disappearing mammals. It is a theory now being tested by grazing ponies on Siberian tundra.

There is an interesting parallel in parts of Africa. The great grass plains teeming with wildlife that we associate with east Africa are actually, according to David Western, head of the Kenya Wildlife Service, artificial. Men with fire made them and kept the forest and scrub at bay. Perhaps elephants played a part, too, because elephants have a habit of moving into a national park, tearing down many of the trees and leaving a grassland behind, as they did in Amboseli. Perhaps it was once the same in Eurasia and North America. Perhaps the mammoths kept opening up the forest and tundra and turning them into steppe. When the mammoths were gone, there was nothing to stop the spread of gloomy spruce trees. (Come to think of it, that's another reason to bring back the mammoth-to annoy the Forestry Commission.)

If the Russians are right, half the evidence for the climate theory vanishes at once: changes in vegetation do not reflect changes in climate but the hunting to extinction of the mammals. The great oak woods of Britain that our ancestors laboriously cleared might have become much more like steppes if our ancestors had not cleared out the mammoths, too.

The climate theory has other flaws. It cannot explain why mammoths survived so much longer on Wrangel island, north of Siberia, where the last ones died just about the time the great pyramids were being built in Egypt. (These Wrangel mammoths were tiny-the size of small ponies-as large mammals confined to islands often are. Mediterranean islands once had tiny elephants and the Channel Islands had miniature deer.) Wrangel island suffered the same climate changes as the mainland, but the sea crossing kept people out for thousands of years.

Nor can the climate theory explain why mammals happily and easily adjusted to warmer climates in previous interglacial periods, but not in this one. It cannot explain why Africa, our continent of origin, was largely immune from the extinction wave and Eurasia, our second home, saw a much more gradual process of extinction. It cannot explain why the extinctions in North America happened before those in South America. And it cannot explain why Australia, New Zealand, Hawaii and Madagascar also suffered waves of extinction at different times, but always coincident with the arrival of human beings.

The facts have long been unambiguous. Climate played little role if any in the extinction of the big mammals and it is only wishful thinking and political correctness that keeps it alive as a hypothesis: wishful thinking that climate change has drastic ecological effects with which to warn us about the future; and a politically correct bias that native Americans are natural conservationists.

There have now been four separate studies to test the theory that native people employ ritual and religion to conserve wildlife. Each has concluded that there is no truth in the idea. Religion, if anything, seems to encourage irresponsible opportunism by absolving hunters of the blame for the scarcity of wildlife and blaming gods instead. It is true that native people can show deliberate management of wild resources such as valuable fruiting trees, canoe-wood trees or egg harvesting sites-but only (a) when these are stationary, and (b) when there is a proper system of private property. This is not a message environmentalists want to hear: it is uncomfortably Thatcherite.

There is no more poignant illustration of the subjectivity of much modern environmentalism than the story of Chief Seattle's speech. Chief Seattle, leader of the Duwamish tribe, delivered a speech to the governor of Washington territory in 1854. Various versions of it are often quoted, one of the most moving being that which Al Gore quoted in his book Earth in the Balance:

Every part of this earth is sacred to my people. Every shining pine needle, every sandy shore, every mist in the dark woods, every meadow, every humming insect. All are holy in the memory and experience of my people... Will you teach your children what we have taught our children? That the earth is our mother? What befalls the earth befalls all the sons of earth. This we know: the earth does not belong to man, man belongs to the earth.

This was an extraordinarily prescient statement of the central theme of deep ecology. But the prescience, alas, is illusory. Nobody knows what Chief Seattle really said that day. The words Gore quoted were written for an ABC television drama by a screenwriter and professor of film, Ted Perry, in 1971.

But the blaming of the Pleistocene overkill on people is not all bad news for environmentalists. On the one hand, it dents the myth of the noble savage, and with it the utopian dream of a spiritual readjustment of modern society to rediscover a way of living in harmony with nature-the sort of thing the Pope, the Prince of Wales, the American vice-president and Jonathon Porritt periodically call for. On the other, it rests still more blame on our species for the extinction crisis. It appears that compared with our ancestors' bows and arrows, our modern bulldozers are rather poor extinguishing tools.