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by Diamond, Jared

  As the southernmost of the Viking North Atlantic colonies except for Vinland, and lying in the Gulf Stream, the Orkneys enjoy a mild climate. Their fertile, heavy soils have been renewed by glaciation and are not at serious risk of erosion. Hence farming in the Orkneys was already being practiced by the Picts before the Vikings arrived, was continued under the Vikings, and remains highly productive to this day. Modern Orkney agricultural exports include beef and eggs, plus pork, cheese, and some crops.

  The Vikings conquered the Orkneys around A.D. 800, proceeded to use the islands as a base for raiding the nearby British and Irish mainlands, and built up a rich, powerful society that remained for some time an independent Norse kingdom. One manifestation of the Orkney Vikings’ wealth is a 17-pound cache of silver buried around A.D. 950, unmatched on any other North Atlantic island and equal in size to the largest silver caches of mainland Scandinavia. Another manifestation is St. Magnus Cathedral, erected in the 12th century and inspired by Britain’s mighty Durham Cathedral. In A.D. 1472 ownership of the Orkneys passed without conquest from Norway (then subject to Denmark) to Scotland, for a trivial reason of dynastic politics (Scotland’s King James demanded compensation for Denmark’s failure to pay the dowry promised to accompany the Danish princess whom he married). Under Scottish rule, the Orkney islanders continued to speak a Norse dialect until the 1700s. Today, the Orkney descendents of indigenous Picts and Norse invaders remain prosperous farmers enriched by a terminal for North Sea oil.

  Some of what I have just said about the Orkneys also applies to the next North Atlantic colony, the Shetland Islands. They too were originally occupied by Pict farmers, conquered by Vikings in the ninth century, ceded to Scotland in 1472, spoke Norse for some time thereafter, and have recently profited from North Sea oil. Differences are that they are slightly more remote and northerly (50 miles north of Orkney and 130 miles north of Scotland), windier, have poorer soils, and are less productive agriculturally. Raising sheep for wool has been an economic mainstay in the Shetlands as in the Orkneys, but raising cattle failed in the Shetlands and was replaced by increased emphasis on fishing.

  Next in isolation after the Orkneys and Shetlands were the Faeroe Islands, 200 miles north of the Orkneys and 400 miles west of Norway. That made the Faeroes still readily accessible to Viking ships carrying settlers and trade goods, but beyond reach of earlier ships. Hence the Vikings found the Faeroes uninhabited except perhaps for a few Irish hermits, about whose existence there are vague stories but no firm archaeological evidence.

  Lying 300 miles south of the Arctic Circle, at a latitude intermediate between that of the two largest towns on Norway’s west coast (Bergen and Trondheim), the Faeroes enjoy a mild oceanic climate. However, their more northerly location than that of the Orkneys and Shetlands meant a shorter growing season for would-be farmers and herders. Salt spray from the ocean, blown onto all parts of the islands because of their small area, combined with strong winds to prevent the development of forests. The original vegetation consisted of nothing taller than low willows, birches, aspen, and junipers, which were quickly cleared by the first settlers and prevented from regenerating by browsing sheep. In a drier climate that would have been a recipe for soil erosion, but the Faeroes are very wet and foggy and “enjoy” rain on an average of 280 days each year, including several rain showers on most days. The settlers themselves also adopted policies to minimize erosion, such as building walls and terraces to prevent soil loss. Viking settlers in Greenland and especially in Iceland were much less successful in controlling erosion, not because they were more imprudent than Faeroe Islanders but because Iceland soils and Greenland climate made the risk of erosion greater.

  Vikings settled the Faeroes during the ninth century. They managed to grow some barley but few or no other crops; even today, only about 6% of the land area of the Faeroes is devoted to growing potatoes and other vegetables. The cows and pigs prized in Norway, and even the low-status goats, were abandoned by the settlers within the first 200 years to prevent overgrazing. Instead, the Faeroe economy became focused on raising sheep to export wool, supplemented later by export of salt fish, and today of dried cod, halibut, and farmed salmon. In return for those wool and fish exports, the islanders imported from Norway and Britain the bulk necessities that were lacking or deficient in the Faeroe environment: especially, huge quantities of wood, because no construction timber was locally available except for driftwood; iron for tools, also completely lacking locally; and other stones and minerals, such as grindstones, whetstones, and soft soapstone out of which to carve kitchenware to replace pottery.

  As for the Faeroes’ history after settlement, the islanders converted to Christianity around A.D. 1000, i.e., around the same time as the other Viking North Atlantic colonies, and later they constructed a Gothic cathedral. The islands became tributary to Norway in the 11th century, passed with Norway to Denmark in 1380 when Norway itself came under the Danish crown, and achieved self-government under Denmark in 1948. The 47,000 inhabitants today still speak a Faeroese language, directly derived from Old Norse and very similar to modern Icelandic; Faeroese and Icelanders can understand each other’s speech and Old Norse texts.

  In short, the Faeroes were spared the problems that beset Norse Iceland and Greenland: the erosion-prone soils and active volcanoes of Iceland, and the shorter growing season, drier climate, much greater sailing distances, and hostile local population of Greenland. While more isolated than the Orkneys or Shetlands, and poorer in local resources compared especially to the Orkneys, Faeroe islanders survived without difficulty by importing large quantities of necessities—an option not open to the Greenlanders.

  The purpose of my first visit to Iceland was to attend a NATO-sponsored conference on restoring ecologically damaged environments. It was especially appropriate that NATO had chosen Iceland as the conference’s site, because Iceland is ecologically the most heavily damaged country in Europe. Since human settlement began, most of the country’s original trees and vegetation have been destroyed, and about half of the original soils have eroded into the ocean. As a result of that damage, large areas of Iceland that were green at the time that Vikings landed are now lifeless brown desert without buildings, roads, or any current signs of people. When the American space agency NASA wanted to find some place on Earth resembling the surface of the moon, so that our astronauts preparing for the first moon landing could practice in an environment similar to what they would encounter, NASA picked a formerly green area of Iceland that is now utterly barren.

  The four elements that form Iceland’s environment are volcanic fire, ice, water, and wind. Iceland lies in the North Atlantic Ocean about 600 miles west of Norway, on what is called the Mid-Atlantic Ridge, where the American and Eurasian continental plates spread and where volcanoes periodically rise from the ocean to build up chunks of new land, of which Iceland is the largest. On the average, at least one of Iceland’s many volcanoes undergoes a major eruption every decade or two. Besides the volcanoes themselves, Iceland’s hot springs and geothermal areas are so numerous that much of the country (including the entire capital of Reykjavík) heats its houses not by burning fossil fuels but just by tapping volcanic heat.

  The second element in Iceland’s landscape is ice, which forms and remains as ice caps on much of Iceland’s interior plateau because it is at high elevation (up to 6,952 feet high), just below the Arctic Circle, and hence cold. Water falling as rain and snow reaches the ocean in glaciers, in rivers that periodically flood, and in occasional spectacular superfloods when a natural dam of lava or ice across a lake gives way, or when a volcanic eruption under an ice cap suddenly melts a lot of ice. Finally, Iceland is also a very windy place. It is the interaction between these four elements of volcanoes, cold, water, and wind that has made Iceland so susceptible to erosion.

  When the first Viking settlers reached Iceland, its volcanoes and hot springs were strange sights, unlike anything known to them in Norway or the British Isles, but otherwise t
he landscape looked familiar and encouraging. Almost all of the plants and birds belonged to familiar European species. The lowlands were mostly covered by low birch and willow forest that was easily cleared for pastures. In those cleared locations, in natural low-lying treeless areas such as bogs, and at higher elevations above timber-line the settlers found lush pasture grass, herbs, and moss ideal for raising the livestock that they had already been raising in Norway and the British Isles. The soil was fertile, in some places up to 50 feet deep. Despite the high-altitude ice caps and the location near the Arctic Circle, the nearby Gulf Stream made the climate in the lowlands mild enough in some years to grow barley in the south. The lakes, rivers, and surrounding seas teemed with fish and with never-before-hunted and hence unafraid seabirds and ducks, while equally unafraid seals and walruses lived along the coast.

  But Iceland’s apparent similarity to southwestern Norway and Britain was deceptive in three crucial respects. First, Iceland’s more northerly location, hundreds of miles north of southwestern Norway’s main farmlands, meant a cooler climate and shorter growing season, making agriculture more marginal. Eventually, as the climate became colder in the late Middle Ages, the settlers gave up on crops to become solely herders. Second, the ash that volcanic eruptions periodically ejected over wide areas poisoned fodder for livestock. Repeatedly throughout Iceland’s history, such eruptions have caused animals and people to starve, the worst such disaster being the 1783 Laki eruption after which about one-fifth of the human population starved to death.

  The biggest set of problems that deceived the settlers involved differences between Iceland’s fragile, unfamiliar soils and Norway’s and Britain’s robust, familiar soils. The settlers could not appreciate those differences partly because some of them are subtle and still not well understood by professional soil scientists, but also because one of those differences was invisible at first sight and would take years to appreciate: namely, that Iceland’s soils form more slowly and erode much more quickly than those of Norway and Britain. In effect, when the settlers saw Iceland’s fertile and locally thick soils, they reacted with delight, as any of us would react to inheriting a bank account with a large positive balance, for which we would assume familiar interest rates and would expect the account to throw off large interest payments each year. Unfortunately, while Iceland’s soils and dense woodlands were impressive to the eye—corresponding to the large balance of the bank account—that balance had accumulated very slowly (as if with low interest rates) since the end of the last Ice Age. The settlers eventually discovered that they were not living off of Iceland’s ecological annual interest, but that they were drawing down its accumulated capital of soil and vegetation that had taken ten thousand years to build up, and much of which the settlers exhausted in a few decades or even within a year. Inadvertently, the settlers were not using the soil and vegetation sustainably, as resources that can persist indefinitely (like a well-managed fishery or forest) if harvested no faster than the resources can renew themselves. They were instead exploiting the soil and vegetation in the way that miners exploit oil and mineral deposits, which renew themselves only infinitely slowly and are mined until they are all gone.

  What is it that makes Iceland’s soils so fragile and slow to form? A major reason has to do with their origin. In Norway, northern Britain, and Greenland, which lack recently active volcanoes and were completely glaciated during the Ice Ages, heavy soils were generated either as uplifted marine clays or else by glaciers grinding the underlying rock and carrying the particles, which were later deposited as sediment when the glaciers melted. In Iceland, though, frequent eruptions of volcanoes throw clouds of fine ash into the air. That ash includes light particles that strong winds proceed to carry over much of the country, resulting in the formation of an ash layer (tephra) that can be as light as talcum powder. On that rich fertile ash, vegetation eventually grows up, covering the ash and protecting it from erosion. But when that vegetation is removed (by sheep grazing it or farmers burning it), the ash becomes exposed again, making it susceptible to erosion. Because the ash was light enough to be carried in by the wind in the first place, it is also light enough to be carried out by the wind again. In addition to that wind erosion, Iceland’s locally heavy rains and frequent floods also remove the exposed ash by water erosion, especially on steep slopes.

  The other reasons for the fragility of Iceland’s soils have to do with the fragility of its vegetation. Growth of vegetation tends to protect soil against erosion by covering it, and by adding organic matter that cements it and increases its bulk. But vegetaion grows slowly in Iceland because of its northerly location, cool climate, and short growing season. Iceland’s combination of fragile soils and slow plant growth creates a positive feedback cycle to erosion: after the protective cover of vegetation is stripped off by sheep or farmers, and soil erosion has then begun, it is difficult for plants to reestablish themselves and to protect the soil again, so the erosion tends to spread.

  Iceland’s colonization began in earnest around the year 870 and virtually ended by the year 930, when almost all land suitable for farming had been settled or claimed. Most settlers came directly from western Norway, the remainder being Vikings who had already emigrated to the British Isles and married Celtic wives. Those settlers tired to re-create a herding economy similar to the lifestyle that they had known in Norway and the British Isles, and based on the same five barnyard animals, among which sheep eventually became by far the most numerous. Sheep milk was made into and stored as butter, cheese, and an Icelandic specialty called skyr, which to my taste is like a delicious thick yogurt. To make up the rest of their diet, Icelanders relied on wild game and fish, as revealed again by the patient efforts of zooarchaeologists identifying 47,000 bones in garbage heaps. The breeding walrus colonies were quickly exterminated, and the breeding seabirds became depleted, leaving hunters to shift attention to seals. Eventually, the main source of wild protein became fish—both the abundant trout, salmon, and char in lakes and rivers, and the abundant cod and haddock along the coast. Those cod and haddock were crucial in enabling Icelanders to survive the hard centuries of the Little Ice Age and in driving Iceland’s economy today.

  At the time that settlement of Iceland began, one-quarter of the island’s area was forested. The settlers proceeded to clear the trees for pastures, and for using the trees themselves as firewood, timber, and charcoal. About 80% of that original woodland was cleared within the first few decades, and 96% as of modern times, thus leaving only 1% of Iceland’s area still forested (Plate 16). Big chunks of scorched wood found in the earliest archaeological sites show that—incredible as it seems today—much of the wood from that land clearance was wasted or just burned, until Icelanders realized that they would be short of wood for the indefinite future. Once the original trees had been removed, grazing by sheep, and rooting by the pigs initially present, prevented seedlings from regenerating. As one drives across Iceland today, it is striking to notice how the occasional clumps of trees still standing are mostly ones enclosed by fences to protect them from sheep.

  Iceland’s highlands above tree line, supporting natural grassland on fertile shallow soil, were particularly attractive to the settlers, who didn’t even have to clear trees there in order to create pastures. But the highlands were more fragile than the lowlands, because they were colder and drier, hence had lower rates of plant regrowth, and were not protected by woodland cover. Once the natural carpet of grassland had been cleared or browsed off, the soil originating as windblown ash was now exposed to wind erosion. In addition, water running downhill, either as rain or as snowmelt runoff, could start to erode gullies into the now-bare soil. But as a gully developed and as the water table dropped from the level of the top of the gully to the bottom, the soil dried out and became even more subject to wind erosion. Within a short time after settlement, Iceland’s soils began to be carried from the highlands down to the lowlands and out to sea. The highlands became stripped of soil as well a
s of vegetation, the former grasslands of Iceland’s interior became the man-made (or sheep-made) desert that one sees today, and then large eroded areas started to develop in the lowlands as well.

  Today we have to ask ourselves: why on Earth did those foolish settlers manage their land in ways that caused such obvious damage? Didn’t they realize what would happen? Yes, they eventually did, but they couldn’t at first, because they were faced with an unfamiliar and difficult problem of land management. Except for its volcanoes and hot springs, Iceland looked rather similar to areas of Norway and Britain whence the settlers had emigrated. Viking settlers had no way of knowing that Iceland’s soils and vegetation were much more fragile than what they were used to. It seemed natural to the settlers to occupy the highlands and to stock many sheep there, just as they had in the Scottish highlands: how would they know that Iceland’s highlands couldn’t support sheep indefinitely, and that even the lowlands were being overstocked? In short, the explanation of why Iceland became the European country with the most serious ecological damage is not that cautious Norwegian and British immigrants suddenly threw caution to the winds when they landed in Iceland, but that they found themselves in an apparently lush but actually fragile environment for which their Norwegian and British experience had failed to prepare them.

  When the settlers finally realized what was happening, they did take corrective action. They stopped throwing away big pieces of wood, stopped keeping ecologically destructive pigs and goats, and abandoned much of the highlands. Groups of neighboring farms cooperated in jointly making decisions critical for preventing erosion, such as the decision about when in the late spring the grass growth warranted taking the sheep up to communally owned high-altitude mountain pastures for the summer, and when in the fall to bring the sheep back down. Farmers sought to reach agreement on the maximum number of sheep that each communal pasture could support, and how that number was to be divided among sheep quotas for the individual farmers.