How Many Friends Does One Person Need? (17 page)

Unfortunately, as with all sustainable harvesting schemes, the pressures of economics and everyday survival hover ominously in the background. In the poorer countries of the world where life is on the margin, over-exploitation of one’s natural resources is always a temptation. The problem that confronts most of the people is simply making it through to tomorrow: the future will just have to look after itself. If destroying a natural resource like the
Boswellia
trees allows you to survive today, that’s better than starving while you admire a healthy stand of trees. This natural human instinct is the central problem in conservation. Until we can all enjoy a reasonable standard of living everywhere, the planet will always be fighting a losing battle against the forces of day-to-day survival.

If there is one iconic picture of Ice Age humans, it must surely be that of half a dozen muscled prehistoric cave-men surrounding an angry mammoth which they are trying to spear to death. In the background, there is always a herd of these monsters ambling away into the distance across the tundra, apparently unconcerned. And so it may
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have been. But the sad reality is that these uniquely northern-hemisphere members of the elephant family (they occurred in North America as well as Eurasia) eventually went extinct. Mind you, it is sobering to remember that mammoths were still living on Wrangel Island in the Siberian Arctic just 3,700 years ago.

The classic explanation for the demise of the mammoths was that they were hunted to extinction by humans invading the tundras of the north in the wake of the retreating Ice Age – a phenomenon sometimes known as the ‘Pleistocene Overkill’. The main evidence was that many large animals, including mammoths, disappeared from North America shortly after the first Native Americans arrived some sixteen thousand years ago. But a more recent suggestion has been that it was climate warming that made it impossible for these lumbering giants to find enough food. It has always been difficult to decide between alternative explanations for past events of this kind. However, an answer might now finally be at hand, thanks to the wonders of modern computers. This has come about through a combination of better climate models that allow us to reconstruct past climates, and a better understanding of the mathematics of conservation biology.

David Nogués-Bravo of Madrid’s National Museum of Science and his colleagues used powerful new climate models to backtrack over the last 130,000 years and reconstruct the climate over the mammoth’s entire continental range in Europe and Asia. They used these to determine the climatic conditions that would have been found at all the sites where mammoths are known to have occurred. Their findings suggest a gradual increase in the size of the area with climates suitable for mammoths between
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127,000 years ago and forty-two thousand years ago, followed by a long period of climatic stability during which the mammoth’s geographical range extended down into southern China and even into modern-day Iran and Afghanistan. But between twenty thousand and six thousand years ago, the climate warmed precipitately and by six thousand years ago the mammoths would have been confined to the rim of the Siberian Arctic and a few isolated places in Central Asia.

This marked reduction in mammoth-friendly habitat would inevitably have coincided with a dramatic collapse in the size of the mammoth population. And it is at this point that humans become important. Modern humans had been hunting mammoths ever since they first came across them after breaking out of Africa for the first time some seventy thousand years ago. Nogués-Bravo and his colleagues used mathematical models from conservation biology to estimate the mammoth’s sus-ceptibility to hunting pressure under different kill regimes and population densities. During the phase when mammoths were most abundant, between forty thousand and twenty thousand years ago, human hunters would have had to kill in excess of one mammoth per person in the population every eighteen months to drive the mammoth populations to extinction. But during the later phases around six thousand years ago when mammoth populations were at their lowest ebb, it would only have taken kill rates of less than one mammoth per person every two hundred years to wipe the species out. This is clearly so low that even very occasional hunting would have been enough to tip the mammoths over the brink.
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We know from the archaeological evidence that hunting rates must have been high, for early humans living in the Ukraine fifteen thousand to twenty thousand years ago made extensive use of mammoth bones for building shelters. In some cases, bones were simply used to weigh down the edges of tents. But at Mezhirich in what is now Ukraine, four huts were built with walls and roof supports made out of the leg bones, lower jaws, skulls and tusks of many mammoths. Just these four huts are estimated to contain bones from as many as ninety-five different individuals.

So the lesson for us today is that while the mammoths could easily absorb the hunting pressure put on them by humans when they were abundant, their ability to do so changed abruptly once climate change caused a dramatic drop in their numbers. At that point, even very modest hunting pressure was enough to tip them over the edge of extinction. It remains an object lesson for us today, with the renewed threat of further climate warming putting increasing numbers of rare species at risk.

Languages go extinct just like animals and plants, and we are currently witnessing a major period of language extinctions. Although there are thought to be just under seven thousand languages currently spoken in the world, no fewer than 550 of these are spoken by fewer than a hundred (mostly rather elderly) people and will certainly be extinct within the next decade or two. Perhaps as many as half of all the rest will be extinct within the next century. One of those could well be Gaelic, the language of
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the Scottish Highlands and islands for at least the past thousand years since the western seaboard was colonised by Gaels from Ireland. With only around sixty thousand, invariably bilingual speakers in Britain (ironically, there are more native Gaelic speakers in Canada, whither many Scots emigrated in the nineteenth century), Gaelic is already on the critical list: it will not take many generations of declining use in everyday contexts for it to slip over the edge of oblivion to join Latin, Sanskrit, Pictish (the language previously spoken in the Highlands when the Romans arrived in Britain) and the dinosaurs.

The short answer is yes, and for several different reasons. One is the more general one that we can learn a great deal about the history of language evolution and the historical migrations of peoples from their languages. Some of the world’s more obscure languages have a great deal to tell us, especially when we contrast what the language has to say with what its speakers’ genes tell us about their physical movements. The two are not always the same, because languages can be acquired as a result of trade or conquest.

The history of our own European languages offers examples of every possible combination in response to conquest. The Slavic Lombards and the Germanic Franks – who invaded northern Italy and France, respectively, as the Roman empire collapsed – abandoned their native languages in favour of the more up-market nascent Italian and French of their no doubt reluctant hosts. In contrast, Attila and his Huns apparently made rather more of an
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impression on their hosts, who, despite solid middle European ancestry and genes, adopted with unseemly alacrity the Mongolian language of their new overlords, so giving rise to the Magyar spoken in modern Hungary. Perhaps fortunately for us in Britain, we decided to keep both our original Anglo-Saxon (a Germanic language) and the new-fangled French (a Romance language descended from Latin) brought in by William the Conqueror and his friends in 1066 – which is why English has such a rich vocabulary, since we invariably have a Saxon word (usually short and blunt) and a French word (usually long and flowery) for everything, and so can use them to create subtle shades of meaning.

Languages are also a repository for folk knowledge, some of which can be medically important (aspirin and quinine are well-known examples that were acquired from the Indians of South America). Losing a language before we have had time to search out its pearls of wisdom may lose us valuable products. Recent experiments have revealed, for example, that granny was right all along to insist on doling out chicken broth as a curative for common ailments: it turns out to be packed full of biochemi-cally active ingredients that are very good at combating viral and other infections. Had granny’s language died with her, the folk remedies figured out painstakingly over many generations by her ancestors might well have been lost for ever.

Languages also provide us with a unique window into other cultures. In this, Scots Gaelic offers an unusual example. From the great eighteenth-century poets Duncan Ban MacIntyre and Rob Donn to our own century’s Sorley MacLean, an unusually rich tradition of
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Gaelic poetry has graced the hearths of lairds as much as the humbler turf firesides of an evening ceilidh when the work was done. It’s a remarkable tradition of oral literature, kept only partly aflame today by groups like Capercaillie and Runrig. More remarkable still, in cultural terms, are the waulking songs of the Hebrides that I mentioned in Chapter 7. No other culture has produced anything like these unique women’s work songs, with their extraordinary rhythmic drive, poetic sonority, humour and sense of community. Along with the shimmering brittleness of Gaelic psalm-singing, these songs represent a remarkable cultural flowering in the Western Isles. All this will be lost if Gaelic becomes extinct.

Languages share with biological species many of the same biogeographic and evolutionary properties. Like animal species, languages are more abundant, have smaller geographic ranges and are more tightly packed near the equator than at higher latitudes. One reason for this seems to be that habitats become more seasonal and less predictable at higher latitudes, and this necessitates larger exchange networks to buffer oneself against crop failure. One consequence seems to be a form of ecological competition for niche space.

The pressure to adopt the most common language in a region (especially when backed by political force) leads inexorably to the extinction of the smaller languages. Small languages survive only where you can be self-contained and self-sufficient. For both languages and biological species, remedial action is necessary if we want to stem the extinction tide.
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The great threat to life on earth is, and always has been, climate change. So the world breathed a sigh of relief and emerged from the Montreal climate warming summit in 2005 with at least the promise from everyone, including the USA, to take climate warming seriously and think about how we might take steps to ameliorate its worst effects. Minds were perhaps concentrated by the succession of major disasters of the previous months – the Indian Ocean tsunami, the Kashmir earthquake and Hurricane Katrina. Of the usual suite of major disasters, we missed out only on a serious volcanic eruption.

For natural disasters, 2005 was a worse than average year: some four hundred thousand people were killed by natural disasters, about five times the number killed in an average year. Still, just to set that in perspective, it’s sobering to remember that well over a million people are killed each year on the world’s roads, and around eight million children die of preventable childhood illnesses.

On the grander scale of the earth’s history, however, dramatic changes in climate are by no means unusual. Everyone knows about the Ice Ages that intermittently engulfed most of northern Europe in massive sheets of ice. In fact, these came and went on a roughly sixty-thousand-year cycle, intermingling the grip of super-win-ter with rather more balmy climatic conditions. Indeed, we are in the middle of just such a balmy period now. The last Ice Age ended around ten thousand years ago with the rather dramatic Younger Dryas Event when the earth’s average temperature rose by a staggering 7oC in just fifty years. It resulted in sea-level rises in excess of
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three hundred feet when the ice locked up in the polar ice sheets melted. By comparison, the current forecast of a four degrees’ temperature rise by 2080 is quite modest.

But take an even bigger step back if you want to see just how unusual today’s climate really is. Measurements of the relative abundance of different carbon isotopes in seashells indicate that between sixty million years ago (when the ill-fated dinosaurs finally died out) and around forty million years ago the average temperature of the earth was around 30oC, double its current value. Europe and North America boasted tropical forests. The earliest lemur-like primates scampered through these forests, while hippos wallowed in the steamy swamps below, right there in the heart of London, Paris and Berlin. On the longer timescale, the current cool phase is in fact quite unusual.

So whether or not our industrial and agricultural activities have caused the current warming, we would do well to remember that the earth’s climate is naturally unstable. Our real problem is how we cope with these changes as they occur. The optimists will want to rely on science. After all, they might say, science has already got us out of one such mess.

Nearly two centuries ago, Thomas Malthus stirred a few feathers by pointing out that the world was heading for disaster because agricultural productivity couldn’t keep step with the rate at which the population was increasing. Darwin was greatly influenced by Malthus when he was writing his
Origin of Species
: it provided him with the insight as to how natural selection might work. But not everyone was as convinced by Malthus as Darwin was. Many were sceptical and argued that the nascent sciences would solve the problem of food production for us.
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As it turned out, the sceptics proved to be right, because science bought us time. A lot of frenetic activity down on the farm gave us the Aberdeen Angus and the Belted Galloway, the Blackface sheep, new and improved ploughs and seed drills. It enabled us to produce a great deal more off each acre of land than our medieval forebears could even have dreamed about, and it finally did away with the Highland ‘ferm touns’ and the old rig systems of medieval agriculture.