Did past changes in climates have major effects on human history? The question has been argued for a century or more, with numerous specific cases used as examples: the end of the Harappan civilization in northern India about 2200 BC, the fall of Mycenaean Greece about 1200 BC, and the rise of the great highland empires of the Andes. At a more distant time, it was proposed that the "bracing" semi-arctic climates of Ice Age Europe produced human populations that were world leaders in both biological and cultural development.
The apparent European lead in development turned out to be merely a product of the large amount of archaeology carried out in Europe as compared with other areas. It is now apparent that the Ice Age inhabitants of most of the Old World were developing in much the same way at the same time. In each of the other cases examined, the evidence of a climatic effect on human history is not conclusive. Since the last Ice Age, climatic change has been relatively small changes of a few degrees in mean annual temperature, or of a few centimetres in mean annual precipitation. At the same time, human populations have developed complex methods of dealing with and adapting to changes in their environment: altenng agricultural habits, trading with neighbouring peoples to obtain necessary resources, and invading neighbouring lands for the same reason. In most cases, archaeology is simply not capable of detecting whether or not a specific instance of social or technological change in the past was a response to changes in the climate or the environment.
Arctic Canada may be a special case. This is, arguably, the most climatically marginal region ever occupied by humans. In prehistoric times, it was occupied by peoples who had relatively little social or technological "insulation" between themselves and their environment. When an unexpectedly warm or cold season produced changes in the availability of the animals on which they depended for food and clothing, they could not turn to stored reserves or obtain supplies from distant regions where conditions had not deteriorated. Consequently, it is an area in which a few "bad years" may be expected to have had a more disastrous effect on human populations than a similar period in regions where the climate was more moderate and resources more stable. The archaeology of the Arctic does, in fact, suggest that several events in the history of human occupation of the region were related to changes in past climates.
By about 7000 years ago the massive glaciers of the last Ice Age had retreated to the mountain peaks of the eastern Canadian Arctic. Tundra vegetation had become established, and was grazed by caribou, muskoxen, and, in some areas, by bison. The gulfs and channels between the arctic islands had long been at least seasonally ice-free, and provided a home to populations of seals, walrus, and whales. There is considerable evidence that for the next 3500 years the arctic climate was noticeably warmer than today, the tree-line was north of its present position, sea ice was less extensive, and animal populations were large and well established.
Although arctic Canada was habitable by human hunters throughout this period, only the southern fringes of the area were occupied. In the area known as the "barren grounds", between the Mackenzie River and Hudson Bay, we find the remnants of small campsites and scatters of broken or lost spear points and other tools chipped from hard stone. These tools resemble those used at the time by Indian hunters of the northern Plains, and we assume that the first occupation of the area was by Indians. Their way of life was probably similar to that of the Chipewyan who guided Samuel Hearne through the barren grounds in the 1770s: small wandering groups spending their summers on the tundra, hunting caribou southward to the shelter of the forests, where they wintered in skin tents heated with wood fires. The first occupants of the barren grounds, like the later Chipewyan, probably could not survive on the winter tundra. The far northern mainland and the arctic archipelago remained devoid of humans for the following 3000 years. It would be the last major region of the world to remain uninhabited, waiting for a people capable of living their entire lives in the country to the north of the forests.
Such a people arrived in arctic North America about 200 BC. They are known to archaeologists as the Palaeoeskimos (Old Eskimos), although it is very unclear whether they were ancestral to recent Eskimo (Inuit) populations. They came out of Siberia, and this first truly arctic human adaptation was probably made possible by two items of Old World technology: the men carried the bow-and-arrow, a hunting weapon more efficient than New World spears and lances, and the women made tailored skin clothing which was much warmer than that used by northern Indians of the time. From the maritime hunters of the North Pacific and the Bering Sea they had learned how to harpoon sea mammals and use their fat and bones to fuel small fires. The meagreness of their archaeological remains suggests that they also brought with them an ethic of tolerance for a much higher degree of discomfort and insecurity than would be considered acceptable to most human populations.
The Palaeoeskimos spread rapidly across the Arctic, probably finding easy hunting among animals that had never before seen humans. Within what may have been only a few generations, a thin network of tiny bands stretched across all of arctic Canada save for the islands of the far northwestern archipelago. This occupation continued until approximately 1500 BC, when there seems to have been a marked southern shift in arctic occupations: the islands of the High Arctic, those north of Lancaster Sound, were abandoned by the Palaeoeskimos, while the barren grounds were apparently abandoned by Indians. This occurred at a time when the tree-line to the west of Hudson Bay retreated considerably to the South, and there is evidence of a cooling climate throughout the Arctic. The retreat of the tree-line was probably quite rapid, caused by the massive burning of forests already dead or dying from increased cold. Such an event must have caused great disruption in the annual migrations of the caribou. For the people who awaited the caribou at the crucial autumn killing-places, changes in migration patterns must have meant hardship and, in many cases, the starvation of local groups. For the next few centuries there are no traces of Indian hunters in the barren grounds, but their place was taken by Palaeoeskimos who moved southward from the arctic coast and occupied the interior tundra and forest as far south as Lake Athabasca and northern Manitoba. Clearly, these were people who had no trouble surviving in the southern Arctic, even during times of cold climates and scarce animal resources.
The next major event in arctic prehistory also occurred during a period of climatic change, but the change seems to have affected cultural development in an unexpected manner. After a few centuries of warmer conditions, during which Indians reclaimed the barren grounds and Palaeoeskimos reoccupied the islands of the High Arctic, the climate became colder once again in the centuries around 500 BC. Archaeological remains from this period of Palaeoeskimo occupation are numerous, and the sites suggest expanding populations, a more settled lifestyle, and a more secure economic base.
An explanation for this apparent paradox may lie in the fact that, although food resources probably did not increase in a period of cooling climate, they may have become more easily available to a people with the technology of the Palaeoeskimos. There is little evidence that the Palaeoeskimos of this period used kayaks, nor did they have the float-harpoon technology used by the later Inuit to hunt large sea mammals. Although they were expert hunters of seals, and could capture animals as large as walrus and beluga, their sea hunting must have been carried out from shore and, much more importantly, from the sea ice.
We know that in today's Arctic cool summers produce a marked increase in the extent and seasonal duration of sea ice, and we can expect that cooler summers in the past would have had a similar effect. This, in turn, can be expected to have produced three major results. First, a decrease in evaporation could have caused colder and drier summer weather which, in the near-desert of the arctic islands, would have meant less vegetation and fewer caribou and muskoxen. Second, more extensive sea ice could have caused an increase in populations of ringed seals, animals that were the mainstay of most traditional Inuit diets, and which are dependent on stable sea ice for raising their young. Finally, the same sea ice could have provided a safe platform from which people could hunt seals and other marine mammals over much greater areas, and for a longer season than in warmer periods.
The Palaeoeskimos seem to have adapted well to such a situation. There is evidence suggesting that they became less dependent on land animals and, indeed, that they even stopped using the bow-and-arrow. The bones of seals dominate the refuse scattered about most archaeological sites of the period, and the large amounts of refuse indicate that their settlements were larger and more stable. This successful adaptation of the Palaeoeskimos to colder conditions should be a warning against making facile assumptions that a cooling climate automatically produces hardship for northern hunters.
Europeans and Inuit
The final scenes of arctic prehistory are played out against a background of climatic change well known from European history: the Medieval Warm Period, in the centuries around AD lOOO, and the Little Ice Age between approximately AD 1600 and AD 1850. The Medieval Warm Period brought two new groups to arctic North America, both of them maritime peoples who took advantage of the decreased sea ice of the period. From the east came the Norse, who colonized south-western Greenland and made at least occasional forays along the coasts of the eastern Canadian Arctic and sub-Arctic. From the west came the ancestors of the Inuit, who quickly displaced the Palaeoeskimos from most arctic regions.
The Inuit came from the north-western coasts of Alaska, where their ancestors had developed efficient techniques and equipment for open-water hunting. Animals as large as the bowhead whale were hunted from kayaks and umiaks, skin-covered boats 10 metres or more in length, using large harpoons attached to floats and drags similar to those used by later European whalers. The umiak could also be used to transport an entire camp with all of its equipment, the women rowing the boat while the hunters travelled by kayak. By boat in summer and by dogsled in winter, the early Inuit spread rapidly across the Arctic. The remains of their winter villages-groups of boulder-walled, semi-subterranean houses raftered with the mandibles of whales and surrounded by the discarded bones of whales and other animals- are the most impressive archaeological remains found in arctic Canada, and attest to an economy considerably richer and more secure than that of most Inuit of the historic period.
During the Medieval Warm Period, normal summer conditions were probably similar to those which occur in occasional warm and ice-free summers at the present time. Such pleasant summers began to occur less frequently after about AD 120O, and were extremely rare during the ensuing Little Ice Age. As the deteriorating climate decreased the viability of the already marginal Norse farming in Greenland and increased ice in the North Atlantic interfered with navigation to Europe, the Norse colonies declined, and finally died out some time around AD 1500. At about the same time, the Inuit abandoned the islands of the High Arctic; in other regions they made rapid changes in their lifestyle in an attempt to cope with the new conditions.
In most arctic regions, the Inuit stopped hunting large whales, probably because increased sea ice prevented the regular movement of whales into the area. Sea ice that was more extensive and lasted for much of the summer made open-water hunting less productive, and in some areas the Inuit began to spend summers in the interior, fishing and hunting caribou. Unable to store much food from such summer hunts, they began to abandon their winter villages of permanent houses. More often, winters were spent in temporary snow-house villages on the sea ice, and the people became increasingly dependent on the small ringed seals which winter beneath the ice. Some groups left the sea entirely, and, much like the Palaeoeskimos during a cold period 3000 years earlier, began spending the whole year hunting caribou in the barren grounds. The Inuit lifeways described by European explorers were, therefore, not the result of an ancient adaptation to the Arctic. Rather, they were the product of rapid and makeshift adaptation to the climatic conditions of the Little Ice Age, an adaptation which forced a marked reduction in what had previously been a relatively rich and secure way of life.
Adapting to Climate
The major episodes of arctic prehistory- the first visits by Indian hunters, their replacement by Palaeoeskimos who could survive year-round in arctic conditions, and the Inuit invasion which, in turn, displaced the Palaeoeskimos-cannot be explained by the influences of a changing climate. These episodes are clearly the result of human abilities to invent and adapt technologies. Yetwithin these episodes, it is also apparent that minor changes in climate had a distinct influence on the way in which human life developed in the arctic regions. Although the current occupants of the Arctic have much greater technological insulation between themselves and their environment, the differences between a "good year" and a "bad year" are still important. Climatic changes on the same scale as those that have occurred over the past few millennia can be expected to continue in the future, and will continue to shape the nature of human settlement in arctic Canada.
Robert McGhee is Head of Scientific Section, Archaeological Survey of Canada, Canadian Museum of Civilization, Ottawa.