Collapse: How Societies Choose to Fail or Succeed

by Jared Diamond

  But other parts of the Viking story are equally romantic and more relevant to this book. Besides being feared pirates, the Vikings were farmers, traders, colonizers, and the first European explorers of the North Atlantic. The settlements that they founded met very different fates. Viking settlers of Continental Europe and the British Isles eventually merged with local populations and played a role in forming several nation-states, notably Russia, England, and France. The Vinland colony, representing Europeans’ first attempt to settle North America, was quickly abandoned; the Greenland colony, for 450 years the most remote outpost of European society, finally vanished; the Iceland colony struggled for many centuries through poverty and political difficulties, to emerge in recent times as one of the world’s most affluent societies; and the Orkney, Shetland, and Faeroe colonies survived with little difficulty. All of those Viking colonies were derived from the same ancestral society: their differing fates were transparently related to the different environments in which the colonists found themselves.

  Thus, the Viking expansion westwards across the North Atlantic offers us an instructive natural experiment, just as does the Polynesian expansion eastwards across the Pacific (map, pp. 182-183). Nested within this large natural experiment, Greenland offers us a smaller one: the Vikings met another people there, the Inuit, whose solutions to Greenland’s environmental problems were very different from those of the Vikings. When that smaller experiment ended five centuries later, Greenland’s Vikings had all perished, leaving Greenland uncontested in the hands of the Inuit. The tragedy of the Greenland Norse (Greenland Scandinavians) thus carries a hopeful message: even in difficult environments, collapses of human societies are not inevitable: it depends on how people respond.

  The environmentally triggered collapse of Viking Greenland and the struggles of Iceland have parallels with the environmentally triggered collapses of Easter Island, Mangareva, the Anasazi, the Maya, and many other pre-industrial societies. However, we enjoy advantages in understanding Greenland’s collapse and Iceland’s troubles. For Greenland’s and especially Iceland’s history, we possess contemporary written accounts from those societies as well as from their trade partners—accounts that are frustratingly fragmentary, but still much better than our complete lack of written eyewitness records for those other pre-industrial societies. The Anasazi died or scattered, and the society of the few surviving Easter Islanders became transformed by outsiders, but most modern Icelanders are still the direct descendants of the Viking men and their Celtic wives who were Iceland’s first settlers. In particular, medieval European Christian societies, such as those of Iceland and Norse Greenland, that evolved directly into modern European Christian societies. Hence we know what the church ruins, preserved art, and archaeologically excavated tools meant, whereas much guesswork is required to interpret archaeological remains of those other societies. For instance, when I stood within an opening in the west wall of the well-preserved stone building erected around A.D. 1300 at Hvalsey in Greenland, I knew by comparison with Christian churches elsewhere that this building too was a Christian church, that this particular one was an almost exact replica of a church at Eidfjord in Norway, and that the opening in the west wall was the main entrance as in other Christian churches (Plate 15). In contrast, we can’t hope to understand the significance of Easter Island’s stone statues in such detail.

  The fates of Viking Iceland and Greenland tell an even more complex, hence more richly instructive, story than do the fates of Easter Island, Mangareva’s neighbors, the Anasazi, and the Maya. All five sets of factors that I discussed in the Prologue played a role. The Vikings did damage their environment, they did suffer from climate changes, and their own responses and cultural values did affect the outcome. The first and third of those three factors also operated in the histories of Easter and Mangareva’s neighbors, and all three operated for the Anasazi and the Maya, but in addition trade with friendly outsiders played an essential role in the histories of Iceland and Greenland as of Mangareva’s neighbors and the Anasazi, although not in Easter Island and Maya history. Finally, among these societies, only in Viking Greenland did hostile outsiders (the Inuit) intervene crucially. Thus, if the histories of Easter Island and Mangareva’s neighbors are fugues weaving together two and three themes respectively, as do some fugues by Johann Sebastian Bach, Iceland’s troubles are a quadruple fugue, like the mighty unfinished fugue with which the dying Bach meant to complete his last great composition, the Art of the Fugue. Only Greenland’s demise gives us what Bach himself never attempted, a full quintuple fugue. For all these reasons, Viking societies will be presented in this chapter and the next two as the most detailed example in this book: the second and larger of the two sheep inside our boa constrictor.

  The prelude to the Iceland and Greenland fugues was the Viking explosion that burst upon medieval Europe after A.D. 793, from Ireland and the Baltic to the Mediterranean and Constantinople. Recall that all the basic elements of medieval European civilization arose over the previous 10,000 years in or near the Fertile Crescent, that crescent-shaped area of Southwest Asia from Jordan north to southeastern Turkey and then east to Iran. From that region came the world’s first crops and domestic animals and wheeled transport, the mastery of copper and then of bronze and iron, and the rise of towns and cities, chiefdoms and kingdoms, and organized religions. All of those elements gradually spread to and transformed Europe from southeast to northwest, beginning with the arrival of agriculture in Greece from Anatolia around 7000 B.C. Scandinavia, the corner of Europe farthest from the Fertile Crescent, was the last part of Europe to be so transformed, being reached by agriculture only around 2500 B.C. It was also the corner farthest from the influence of Roman civilization: unlike the area of modern Germany, Roman traders never reached it, nor did it share any boundary with the Roman Empire. Hence, until the Middle Ages, Scandinavia remained Europe’s backwater.

  Yet Scandinavia possessed two sets of natural advantages awaiting exploitation: the furs of northern forest animals, seal skins, and beeswax prized as luxury imports in the rest of Europe; and (in Norway as in Greece) a highly indented coastline, making travel by sea potentially faster than travel by land, and offering rewards to those who could develop seafaring techniques. Until the Middle Ages, Scandinavians had only oar-propelled rowboats without sails. Sailboat technology from the Mediterranean finally reached Scandinavia around A.D. 600, at a time when climatic warming and the arrival of improved plows happened to be stimulating food production and a human population explosion in Scandinavia. Because most of Norway is steep and mountainous, only 3% of its land area can be used for agriculture, and that arable land was coming under increasing population pressure by A.D. 700, especially in western Norway. With decreasing opportunities to establish new farms back at home, Scandinavia’s growing population began expanding overseas. Upon the arrival of sails, Scandinavians quickly developed fast, shallow-draft, highly maneuverable, sailed-and-rowed ships that were ideal for carrying their luxury exports to eager buyers in Europe and Britain. Those ships let them cross the ocean but then also pull up on any shallow beach or row far up rivers, without being confined to the few deepwater harbors.

  But for medieval Scandinavians, as for other seafarers throughout history, trading paved the way for raiding. Once some Scandinavian traders had discovered sea routes to rich peoples who could pay for furs with silver and gold, ambitious younger brothers of those traders realized that they could acquire that same silver and gold without paying for it. Those ships used for trade could also be sailed and rowed over those same sea routes to arrive by surprise at coastal and riverside towns, including ones far inland on rivers. Scandinavians became Vikings, i.e., raiders. Viking ships and sailors were fast enough compared to those elsewhere in Europe that they could escape before being overtaken by the locals’ slower ships, and Europeans never attempted counterraids on the Viking homelands to destroy their bases. The lands that are now Norway and Sweden were then not yet united under sing
le kings, but were still fragmented among chiefs or petty-kings eager to compete for overseas booty with which to attract and reward followers. Chiefs who lost in the struggle against other chiefs at home were especially motivated to try their luck overseas.

  The Viking raids began abruptly on June 8, A.D. 793, with an attack on the rich but defenseless monastery of Lindisfarne Island off the northeast English coast. Thereafter, the raids continued each summer, when the seas were calmer and more conducive to sailing, until after some years the Vikings stopped bothering to return home in the autumn but instead made winter settlements on the targeted coast so that they could begin raiding earlier in the next spring. From those beginnings arose a flexible mixed strategy of alternative methods to acquire wealth, depending on the relative strengths of the Viking fleets and the targeted peoples. As the strength or number of Vikings relative to locals increased, the methods progressed from peaceful trading, through extorting tribute in return for a promise not to raid, to plundering and retreating, and culminated in conquest and the establishment of overseas Viking states.

  Vikings from different parts of Scandinavia went raiding in different directions. Those from the area of modern Sweden, termed Varangians, sailed east into the Baltic Sea, navigated up rivers flowing from Russia into the Baltic, continued south to reach the heads of the Volga and other rivers flowing into the Black Sea and Caspian Sea, traded with the rich Byzantine Empire, and founded the principality of Kiev that became the forerunner of the modern Russian state. Vikings from modern Denmark sailed west to the coast of northwest Europe and the east coast of England, found their way up the Rhine and Loire rivers, settled at their mouths and in Normandy and Brittany, established the Danelaw state in eastern England and the Duchy of Normandy in France, and rounded the Atlantic coast of Spain to enter the Mediterranean at the Straits of Gibraltar and raid Italy. Vikings from modern Norway sailed to Ireland and the north and west coast of Britain and set up a major trading center at Dublin. In each area of Europe the Vikings settled, intermarried, and gradually became assimilated into the local population, with the result that Scandinavian languages and distinct Scandinavian settlements eventually disappeared outside of Scandinavia. Swedish Vikings merged into the Russian population, Danish Vikings into the English population, while the Vikings who settled in Normandy eventually abandoned their Norse language and began speaking French. In that process of assimilation, Scandinavian words as well as genes were absorbed. For instance, the modern English language owes “awkward,” “die,” “egg,” “skirt,” and dozens of other everyday words to the Scandinavian invaders.

  In the course of these voyages to inhabited European lands, many Viking ships were blown off-course into the North Atlantic Ocean, which at those times of warm climate was free of the sea ice that later became a barrier to ship navigation, contributing to the fate of the Norse Greenland colony and of the Titanic. Those off-course ships thereby discovered and settled other lands previously unknown either to Europeans or to any peoples: the uninhabited Faeroe Islands some time after A.D. 800 and Iceland around 870; around A.D. 980 Greenland, at that time occupied only in the far north by Native American predecessors of the Inuit known as the Dorset people; and in A.D. 1000 Vinland, an exploration zone encompassing Newfoundland, the Gulf of St. Lawrence, and possibly some other coastal areas of northeastern North America teeming with Native Americans whose presence forced the Vikings to depart after only a decade.

  The Viking raids on Europe declined as their European targets gradually came to expect them and to defend themselves, as the power of the English and French kings and the German emperor grew, and as the rising power of the Norwegian king began to harness his uncontrolled hotbed of plundering chiefs and to channel their efforts into those of a respectable trading state. On the continent, the Franks drove the Vikings from the River Seine in A.D. 857, won a major victory at the Battle of Louvain in modern Belgium in 891, and expelled them from Brittany in 939. In the British Isles the Vikings were thrown out of Dublin in 902, and their Danelaw kingdom in England disintegrated in 954, although it was then reconstituted by further raids between 980 and 1016. The year 1066, famous for the Battle of Hastings at which William the Conqueror (William of Normandy) led French-speaking descendants of former Viking raiders to conquer England, can also be taken to mark the end of the Viking raids. The reason why William was able to defeat the English king Harold at Hastings on England’s southeast coast on October 14 was that Harold and his soldiers were exhausted. They had marched 220 miles south in less than three weeks after defeating the last Viking invading army and killing their king at Stamford Bridge in central England on September 25. Thereafter, the Scandinavian kingdoms evolved into normal states trading with other European states and only occasionally indulging in wars, rather than constantly raiding. Medieval Norway became known not for its feared raiders but for its exports of dried codfish.

  In light of this history that I have related, how can we explain why the Vikings left their homelands to risk their lives in battle or in such difficult environments as that of Greenland? After millennia of their remaining in Scandinavia and leaving the rest of Europe alone, why did their expansion build up so quickly to a peak after 793, and then grind to a complete halt less than three centuries later? With any historical expansion, one can ask whether it was triggered by “push” (population pressure and lack of opportunities at home), “pull” (good opportunities and empty areas to colonize overseas), or both. Many expansion waves have been driven by a combination of push and pull, and that was also true of the Vikings: they were pushed by population growth and consolidation of royal power at home, and pulled by uninhabited new lands to settle and inhabited but defenseless rich lands to plunder overseas. Similarly, European immigration to North America reached its peak in the 1800s and early 1900s through a combination of push and pull: population growth, famines, and political oppression in Europe pushed immigrants from their homelands, while the availability of almost unlimited fertile farmland and economic opportunities in the United States and Canada pulled them.

  As for why the sum of push/pull forces switched so abruptly from unattractive to attractive after A.D. 793, and then subsided so quickly towards 1066, the Viking expansion is a good example of what is termed an autocatalytic process. In chemistry the term catalysis means the speeding-up of a chemical reaction by an added ingredient, such as an enzyme. Some chemical reactions produce a product that also acts as a catalyst, so that the speed of the reaction starts from nothing and then runs away as some product is formed, catalyzing and driving the reaction faster and producing more product which drives the reaction still faster. Such a chain reaction is termed autocatalytic, the prime example being the explosion of an atomic bomb when neutrons in a critical mass of uranium split uranium nuclei to release energy plus more neutrons, which split still more nuclei.

  Similarly, in an autocatalytic expansion of a human population, some initial advantages that a people gains (such as technological advantages) bring them profits or discoveries, which in turn stimulate more people to seek profits and discoveries, which result in even more profits and discoveries stimulating even more people to set out, until that people has filled up all the areas available to them with those advantages, at which point the autocatalytic expansion ceases to catalyze itself and runs out of steam. Two specific events set off the Viking chain reaction: the A.D. 793 raid on Lindisfarne Monastery, yielding a rich haul of booty that in the following year stimulated raids yielding more booty; and the discovery of the unpopulated Faeroe Islands suitable for raising sheep, leading to the discovery of larger and more distant Iceland and then of still larger and more distant Greenland. Vikings returning home with booty or with reports of islands ripe for settlement fired the imagination of more Vikings to set out in search of more booty and more empty islands. Other examples of autocatalytic expansions besides the Viking expansion include the expansion of ancestral Polynesians eastwards over the Pacific Ocean beginning around 1200 B.C., and of
Portuguese and Spaniards over the world beginning in the 1400s and especially with Columbus’s “discovery” of the New World in 1492.

  Like those Polynesian and Portuguese/Spanish expansions, the Viking expansion began to fizzle out when all areas readily accessible to their ships had already been raided or colonized, and when Vikings returning home ceased to bring stories of uninhabited or easily raided lands overseas. Just as two specific events set off the Viking chain reaction, two other events symbolize what throttled it. One was the Battle of Stamford Bridge in 1066, capping a long series of Viking defeats and demonstrating the futility of further raids. The other was the forced abandonment of the Vikings’ most remote colony of Vinland around A.D. 1000, after only a decade. The two preserved Norse sagas describing Vinland say explicitly that it was abandoned because of fighting with a dense population of Native Americans far too numerous to be defeated by the few Vikings able to cross the Atlantic in ships of those times. With the Faeroes, Iceland, and Greenland already full of Viking settlers, Vinland impossibly dangerous, and no more discoveries of uninhabited Atlantic islands being made, the Vikings got the point that there were no longer any rewards to greet pioneers risking their lives in the stormy North Atlantic.

  When immigrants from overseas colonize a new homeland, the lifestyle that they establish usually incorporates features of the lifestyle that they had practiced in their land of origin—a “cultural capital” of knowledge, beliefs, subsistence methods, and social organization accumulated in their homeland. That is especially the case when, as true of the Vikings, they occupy a land that is originally either uninhabited, or else inhabited by people with whom the colonists have little contact. Even in the United States today, where new immigrants must deal with a vastly more numerous established American population, each immigrant group still retains many of its own distinctive characteristics. For instance, within my city of Los Angeles there are big differences between the cultural values, educational levels, jobs, and wealth of recent immigrant groups such as Vietnamese, Iranians, Mexicans, and Ethiopians. Different groups here have adapted with different ease to American society, depending in part on the lifestyle that they brought with them.