The Great Divide Page 11
Nonetheless, Haynes still concurs with Paul Martin. He says that the continental United States ‘contains more mega-mammal kill-sites’ than there are elephant kill-sites in all of Africa, a much larger land-mass.53 Furthermore, not only is Africa bigger but early humans have been around far longer there than the ~13,000+ years that humans have been in the New World (south of the glaciers), at least 100 times in fact, according to him.* Judging by the quantity of fluted points found associated with mammoths and mastodonts, mammoths were more often hunted and scavenged, though this may be because mastodonts occupied wetter territory and the fluted points used to kill them sank deeper into the ground and have not been found.54 Another important observation is that mammoths killed by Clovis hunters were notoriously under-utilised – they were not fully butchered – and this may indicate that they were opportunistically attacked, people reacting to the climatic stresses that were affecting the mega-mammals.
This is one of the rival theories, that climatic change – in particular that the world was warming up and drying out just then – is what killed off the mega-mammals in an entirely natural progression (though Jared Diamond points out that America’s megafauna had already survived the ends of twenty-two previous Ice Ages – what made this one so different?).55 Another theory, published only in 2007, by a team of twenty-five geophysicists, is that a wayward comet hurtled into Earth’s atmosphere around 12900 BP, fractured into pieces and exploded in giant fireballs, producing immense wildfires, killing off both the mega-mammals and the Clovis people, with the population of the New World being reduced by 70 per cent. At eight well-documented Clovis sites, the geophysicists say they found evidence of extraterrestrial debris – including nanodiamonds and carbon molecules containing the rare isotope, helium-3, the former only ever found on Earth in meteorites and the latter far more abundant in the cosmos than on Earth. The chemical signature of wildfire – polycyclic aromatic hydrocarbons – were also found in three sites. Moreover, at no fewer than 70 sites in the United States and Canada a black sedimentary layer (suggesting widespread burning) has been found, dating to 12,900 years ago, with Clovis remains below. This corroborates the idea that there was an extraterrestrial impact at that time and that it had a marked effect on the landscape and on the population of early humans and mega-mammals in the Americas.56
The idea of a population decline has been queried by other studies and Haynes argues that the under-utilisation of the carcasses of mammoths points to the fact that Clovis foragers found it easy to procure them, either by scavenging or by killing, and they did not make full use of meat and other by-products in the way they would have needed to if hunting had been more difficult. The two theories can be put together, of course, in that the mega-mammals may have been slowly starving, progressively weakened by the climatic perturbation that was brought about by the end of the Ice Age. And of course the Clovis people may have chosen weakened or vulnerable animals – a rational decision. Even so, the under-utilisation of the mega-mammals that were killed certainly suggests a source of food in plentiful supply. The later use of totems by certain New World tribes – totems which govern the hunting practices of people in regard to a specific animal, where those practices help preserve the animal in question, to maintain future supplies – may well be a folk memory (and a warning) of circumstances where primary food supplies were wiped out.*
Gary Haynes has also compared the Clovis culture with its contemporaries in the Old World. He makes the fundamental point that the difference in sheer size of Eurasia and the Americas, and the antiquity of the human presence in the Old World, could account for the most important differences, though Eurasia was not as big then as it is now, because ice covered large areas of the north. Even accounting for this, however, there were some instructive differences between Clovis and the late-Pleistocene/early-Holocene cultures of Eurasia.
Of the three most important differences, the first was the widespread presence of artworks, the most striking of which were the so-called ‘Venus figurines’ found in sites distributed from France to the Ukraine. Venus figurines are so called because they exhibit exaggerated anatomical features (these are discussed in more detail in chapter seven). A second difference is the size of settlements. At Dolni Vĕstonice, in the Czech Republic, and dating to 29000–25000 BC, the site contains the bones of at least 150 mammoths, with signs of shelters made from mammoth bones, wood, rocks and dirt, hearths and ashy deposits, indicating fire, more than 2,000 fragments of clay figurines and many other artefacts, both stone and organic.57
Both Gary Haynes and Olga Soffer, the latter at the University of Illinois, argue that there is some overlap between Clovis and the culture known in Europe as Gravettian (named for La Gravette in the Dordogne in France, at 28,000–22,000 years ago). Gravettian was different from Clovis in that the former spread in parts of Europe that had been occupied before, whereas the Clovis people were entering land unoccupied by humans. But both Gravettian culture and Clovis spread over huge geographical regions, meaning they were both very successful adaptations, though there is still a lively disagreement as to whether, in the Gravettian case, this was the spread of people or of ideas. Both Gravettian and Clovis people hunted large mammals such as the mammoth but there is disagreement about the importance of these large animals in the respective diets. In western Europe, the Gravettian faunal record is dominated by reindeer and fur-bearing carnivores (fox and wolf, mainly) but mammoth ‘has a commanding presence’ in Moravia, Poland and the central Russian plain. Clovis faunal lists, as we have seen, are most often dominated by mammoth, with bison and a few other types more rarely represented. Gravettian sites sometimes show elaborate living features ‘and items of personal adornment are relatively abundant’.58
There are also similarities between Clovis and the Solutrean culture (also French, 21,000–17,000 years ago), notably in lithic technology, but Solutrean tools – and Eurasian tools more generally – are comparatively varied and contain forms not found in Clovis sites. However, the most intriguing comparison is with the Magdalénian, named for La Madeleine, in the Vezere Valley, again in the Dordogne part of France, 18,000–10,000 years ago, where flint is carried over long distances, few if any sites are occupied year-round, and there is almost no artwork. Large lithic assemblages are rare, there are next to no houses with hearths and ‘all signs point to very mobile and transient foraging groups’.59
These factors may be put together to conclude that, with the possible exception of a few sites (for example, Shoop in Pennsylvania and Bull Brook in Massachusetts), there are no large Clovis sites (of twenty acres or more) with debris middens, and, again with the possible exception of Gault, Texas, no art or decorative work. Recent studies by Genevieve von Petzinger and April Nowell, at the University of Victoria in British Columbia, created a stir at a Paleoanthropology Society meeting in Chicago in April 2009, when they showed that, alongside the great cave paintings of the Ice Age, some 26 signs had been overlooked but were common at sites stretching from France to South Africa to China to Australia to North and South America. These figures may have had a spiritual significance but, at the moment, their meaning – if they had meaning (and many occur in similar clusters, suggesting that they did) – escapes us.60
This all tends to confirm that the founding population of the New World was very small and very mobile, that it was not repeated, on any scale, and that to begin with it became reliant on a fairly narrow range of mega-mammals – presumably because they were relatively easy to hunt – and that artwork was not developed because there was no need to establish either dedicated territories or tribal identities.61 And/or that food was in such plentiful supply that they had no need to keep records that assisted their memory of animal habits.
• Part Two •
HOW NATURE DIFFERS IN THE OLD WORLD AND THE NEW
• 5 •
RINGS OF FIRE AND THERMAL TRUMPETS
The fact that the New World was devoid of people when the first Americans arrived, was – obviou
sly enough – a matter of crucial importance in accounting for differences between the two hemispheres. But it was not the only one, and perhaps not the most important. We now need to consider the phenomenon of meta-history, the ways in which the broad trajectory of human development has been and is governed by deep forces affecting the entire globe or large areas of it. We have already seen how the orbits of the Earth in relation to the sun determines Ice Ages and interglacials, and the floods which characterise them, and in turn how that has influenced the spread of people across the Earth. And, as was discussed immediately above, the spread and movement of the continents helped to determine the types of animal that evolved around the world. We now need to consider several other of these deep forces.
It has been known for some time, for example, that heat affects life in predictable and important ways. It encourages the proliferation of life forms hostile to man, in particular insects, so that there is a faster transmission of disease in hot countries. In some cases, this is so virulent as to make urban life unviable.1 The unusual spread of temperature and even rainfall patterns mean that farmers in Europe can grow crops all year round.2 In Spain, Portugal, Greece and southern Italy, olive trees and grapes do better than cereals and pasture pays more than agriculture, two factors that may have played a part in hampering those countries’ developments as industrial nations.3 And not until the advent of iron tools could the dense forests north of the Alps be cleared for farming land, which is one reason why northern Europe lagged behind the Mediterranean countries for thousands of years, and then overtook them.4
Broadly speaking, there were – and are – three important ways in which the New World differs from the Old World on such matters. Some are essentially climatological factors, some are geographical factors, and some are the biological results of climate and geography. They are interrelated, and they have influenced the broad sweep of developments in the two hemispheres, everything from food production, to systems of government, to modes of warfare and religious belief. The first and most basic was the weather.
THE ORIGINS OF WEATHER
There are three areas of the world which for the most part govern weather patterns. These are the Pacific Ocean, the North Atlantic and the Himalayan mountain range and the associated Tibetan plateau. Their configuration not only helps shape weather world-wide but has exercised an effect on history by influencing how civilisations developed, where and when.
In a sense, the world’s weather begins in the Pacific. Because of the prevailing trade winds, which blow east-to-west at equatorial latitudes, and because there is a chain of islands running from South East Asia to Australia, at the south-western corner of the Pacific, a ‘pool’ of warm water, many thousands of kilometres across, collects off the Philippines, where it evaporates to create great, dark nimbus clouds which produce the torrential rains known as the monsoon. Monsoon comes from an Arabic word, mausem (season) and traditionally refers to a season of rains moving north in the northern summer, southward in winter. In western India and Pakistan rain showers fall from June to September, sometimes until November, with millions of tropical farmers – in fact, two-thirds of the world’s population of farmers – depending on this circulation.
The north Atlantic is important because, as a look at a map of the world will show, while the Pacific Ocean is effectively cut off from the Arctic region – the Bering Strait is barely sixty miles wide – the Atlantic is thousands of miles wide at its northern extremity. This means that, from time to time, glaciers break off from the polar region and float south, gradually melting. This water evaporates and is born eastward on the prevailing winds, to fall as snow on the Himalayas and the Tibetan plateau. This is the greatest mountain range on earth and there is no other body of land this high, with this extent. The effect of so much snow over such a large area, in central Asia, has the effect of consuming much of the sun’s energy, because the snow has to be melted before the land can be warmed up. It is known that the monsoon strength varies on the 21,000, 43,000 and 100,000-year orbital cycles that were discussed in an earlier chapter but, more to the point, this process has been going on since the last great flood, 8,000 years ago, which released glaciers into the Atlantic in larger numbers than before, and which has had the overall effect that, over that time, the monsoon in Asia has been decreasing in abundance. As we shall see shortly, this decline in the strength of the Asian monsoon – whose effects extend to the eastern end of the Mediterranean and northern/eastern Africa – and the increasing aridity which has ensued, have determined both the rise and fall of several civilisations across the Old World. Using pollen data from western Indian lakes, Reid Bryson and A.M. Swain, from the Center for Climate Research at the University of Wisconsin at Madison, concluded in 1981 that the summer monsoon was at its peak in the early Holocene (10,000–8,000 years ago) but is reduced by as much as two-thirds now.5
The warm pool of water in the south-western corner of the Pacific, off the Philippines, exists where it does in normal years and is complemented by an equally large pool of cold water in the eastern Pacific, off the coast of Chile, Peru and California. The eastern Pacific is normally very cold, even close to the shore, with the result that there is next to no evaporation, and rain clouds rarely form. The Peruvian coast receives virtually no rainfall, and both Mexico’s Baja Peninsula and California have years of almost total drought.6
This dryness had a profound effect on the development of early man in the New World, as we shall see, but, every so often, for reasons that are not entirely clear, this ‘normal’ state of affairs is reversed. The east-west trade winds in the Pacific weaken, or even cease entirely, and are replaced by winds in the opposite direction, from the south-west, which now generate in the Pacific what are known as Kelvin waves, giant undulations below the surface of the ocean, which drive warm water back east towards the Americas. This water flows over the cooler water and warms up the sea surface in striking fashion. Back in the western Pacific, where the waters are now cooler than usual, cloud formation is inhibited and there is drought across South East Asia and in Australia. On the Pacific coast of South America and California, on the other hand, there are severe storms – very severe storms – and a hundred years’ rain can fall in a few days.7
This pattern was first spotted in 1892, when a Peruvian sea captain, Camillo Carrillo, published a short paper in the Bulletin of the Lima Geographical Society, in which he noted that the change in water flow and sea temperature disrupted the anchovy fisheries close inshore (anchovies like cold water). He further noted that the Peruvian sailors, who were aware of this periodic fluctuation, also observed that, when it occurred, it did so just after Christmas-time, and for that reason they had nicknamed the occurrence El Niño, the Christ Child. The phenomenon is now known to scientists as the El Niño Southern Oscillation, or enso (‘oscillation’ because the predominant water movement in the southern Pacific oscillates between east→west and west→east).
El Niño’s effect extends far beyond the Pacific coast of the Americas. The great bulk of warm, moist air that collects over South America during an ENSO is large enough to disrupt the normal air flows across the Earth, bringing heavy rains to much of the North American west coast, keeping arctic air out of other parts of North America, which as a result enjoy unusually mild winters. enso also brings drought to Brazil and parts of Africa.
So the effects of an El Niño event are felt more or less everywhere on Earth. No less important, especially for the subject of this book, just as the Asian monsoon has been getting weaker over the past 8,000 years, so there is evidence that El Niño has been occurring more and more frequently over the past 6,000 years. The two aspects may be linked, in that the chain of islands off South East Asia that separates the Pacific from the Indian Ocean, does allow some water to pass through and, as sea levels have risen over the past 8,000 years, so these islands have let through relatively more water. In an enso event, therefore, when the western Pacific is relatively cold, more cold water is let through into t
he Indian Ocean and this too helps decrease the effect of the monsoon. Studies have shown that droughts occur in India only in El Niño years though not all El Niños bring drought: the link is there but the relationship is still not completely understood.
The evidence tends to show that before 5800 BP, the El Niño phenomenon was very rare. For about 3,000 years after that, they occurred, probably, only once or twice a century. Until the last quarter of the twentieth century, ensos occurred every seven to fifteen years and, at the present time, they happen every two to seven years. This is a remarkable change that is of central importance to our story.
CLIMATE AND CIVILISATION
The evidence that we have at the moment shows most clearly how the monsoon has affected the development of civilisations in Mesopotamia and, moving west to east, the Indus Valley in Pakistan/India, and in China. We also know now to some extent how El Niño has affected the development of civilisation in South America.
The flood plains of the Tigris-Euphrates Rivers are often referred to as the ‘Fertile Crescent’ and are the site of some of the most ancient urban cultures on Earth. The earliest of these, the Ubaid culture, emerged ~7000 BP. However, the Fertile Crescent lies just west of the Asian monsoon system and, after ~5000 BP, when studies show that the climate changed from relatively moist to drought-prone, as affected by the weakening and more variable monsoon conditions, the small farming villages of the early Ubaid culture consolidated into larger settlements.8 There was now a need for more large-scale and integrated irrigation projects (at both local and state levels) to cope with increasingly harsh climatic conditions. Ur was one of the (earliest) cities that emerged at this time – it was thriving around 4600 BP – but its first phase was ended by an attack from the Akkadian empire at around 4340 BP. This too was a time of particularly dry climate, which may have already weakened Ur (though it received much of its wealth from taxation) and may have similarly affected the Akkadians, provoking their attack. We know that Ur continued in existence, as a smaller city-state, but regenerated after about 4110 BP, when the great ziggurat was built, as the temple to Nanna, the moon deity. However, Ur was attacked again in 3950 BP and never recovered. This attack was mounted by the Elam people, based around the city of Susa in what is now south-west Iran, these people themselves having migrated from further east as increasing aridity made life harder on the higher plateaus.