In article after article, academics, policy analysts, and journalists have told a similar story: climate change, by melting Arctic ice, is unlocking resources that could soon trigger war in the far north. They argue that the race to extract the vast reservoirs of oil and natural gas that lie under the vanishing ice – up to a quarter of the world’s undiscovered fossil fuel reserves, by some estimates – will likely provoke hostilities between Russia, the United States, and other nations with claims to the bonanza. The overall failure of early drilling efforts in the Arctic, it seems, is of little consequence.
These claims add a new twist to a vast and growing body of scholarship that links climate change to conflict. Academics working in this area often begin their work by showing that past climate changes reduced – rather than increased – the regional availability of some crucial resource, such as water, or grain, or fish spawning grounds. They then use diverse methods to trace the destabilizing social and political consequences of these resource shortages. Environmental historians, for example, have argued that falling temperatures and changing precipitation patterns in the seventeenth century led to poor grain harvests and famines that provoked rebellions in diverse societies the world over. More controversially, scholars in many disciplines have linked human-caused global warming to droughts that encouraged migration and ultimately conflict in twentieth-century sub-Saharan Africa. Far less attention has been directed at the ways in which more abundant resources might incite violence either within or between states.
In fact, those who make claims about the inevitably more violent nature of the future Arctic have rarely thought to consider the history of climate change and conflict in the far north. Yet violence in the Arctic has long coincided with volcanic eruptions and fluctuations in solar activity that altered regional temperatures and in turn the availability of crucial resources. In the early seventeenth century, for example, the Arctic cooled sharply and then warmed slightly just as Europeans discovered, hunted, and fought over bowhead whales off Spitsbergen, the largest island of the Svalbard archipelago. Oil, bones, and baleen from bowheads became crucial resources for the economies of England and the Dutch Republic.
Diverse manifestations of climate change in the Arctic and Europe influenced how easy bowhead whales were to hunt, the profits that could be fetched by their oil, the proximity of whalers to one another, and the ability of whalers to reach the far north. Skirmishes within and between whaling companies operating from rival European nations reveal that climate change can affect both the causes and the conduct of conflict in diverse ways, even in environments it transforms on a vast scale. There is nothing inevitable or simple about the ways in which climate change influences human decisions and actions.
This history would be hard to investigate without new climate reconstructions compiled by scholars in many different disciplines, using many different sources. In 2014, researchers drew from natural and textual sources to create a sweeping new reconstruction of average Arctic air surface temperatures over the past 2,000 years. It confirms that the Arctic was overall very cold in the seventeenth century, but also that it warmed slightly towards the middle and end of the century. Temperatures in the Arctic therefore roughly mirrored those elsewhere in the Northern Hemisphere during the chilliest century of the “Little Ice Age,” a cooler climatic regime that endured for roughly six centuries. The extent and distribution of sea ice in the Arctic – the most important environmental condition that whalers coped with – would have responded to even subtle changes in average annual temperatures.
Yet these very big trends do not tell us exactly how climate change transformed environments around Svalbard. Local temperature trends do not always precisely mirror regional or global developments, and anyway the distribution and extent of Arctic sea ice registers more than just the warmth or chilliness of the lower atmosphere. Ice core and model simulation data both suggest that air surface temperatures around Svalbard were quite cool in the early seventeenth century and somewhat warmer in the middle of the century, at least in summer. Lakebed sediments, by contrast, suggest that glaciers across Svalbard actually retreated beginning in around 1600 owing to changes in precipitation, not temperature, which may have reduced the local frequency of storms that can break up sea ice. Moreover, sea surface temperatures – which also influence sea ice – were quite warm off the west coast of Spitsbergen, the largest island of the Svalbard archipelago, for much of the seventeenth century, although they were very cold off the northern coast.
Overall, it seems safe to conclude that, in the summer, temperatures around Svalbard roughly mirrored those of the broader Arctic in the seventeenth century. Warmer currents may have brought more nutrients to the region and probably reduced the extent of local sea ice, although a reduction in storm frequency would have preserved the ice that was there. In any case, most Arctic sea ice melts in the summer before reaching its minimum annual extent in the fall, which means that summer weather and currents had the greatest impact on the extent of ice in the Arctic north of Europe. Because sea ice retreated from Svalbard in the summer, it was also the crucial season for whaling.
If the local consequences of global climate changes can be counterintuitive – that warming current off Spitsbergen, for example – so too can human responses. One might assume that climatic cooling would have dissuaded explorers, fishers, and whalers from entering the Arctic. Instead, European sailors found and then started exploiting the environments on and around Svalbard in the late sixteenth and early seventeenth centuries, just as volcanic eruptions led to arguably the coldest point of the Little Ice Age in the Northern Hemisphere. In previous work, I have shown that climate changes in this period interacted with local environments to leave just enough sea ice in the Arctic north of Europe to redirect expeditions in search of an elusive “Northern Passage” to Asia. Dutch and English sailors struggling to find a way through the ice ended up discovering Spitsbergen and the many bowhead whales off its western coast. Bowheads are relatively docile, float on the surface when killed, and have very thick blubber that can be turned into oil. Beginning in 1611, they started attracting Dutch, English, and Basque whalers.
Other scholars have argued that cooling in the early seventeenth century led bowhead whales to congregate along more extensive sea ice near Spitsbergen, which made them easier to hunt for whalers. By contrast, whales dispersed as sea ice retreated in the warmer middle of the seventeenth century, which made them harder to hunt. There does seem to be a statistically significant correlation between ice core reconstructions and model simulations of summer temperatures around Spitsbergen on the one hand, and the annual whale catch on the other. Iñupiat whalers consulted by our own Bathsheba Demuth, however, report that bowheads in the Berring Sea are not social enough to gather in huge groups. Perhaps bowhead culture was different in the Atlantic corner of the Arctic when whale populations were much higher than they are today.
The apparent correlation between surface air temperatures and the whale catch around Spitsbergen provides our first point of entry into relationships between climate change and conflict in the far north. From the first years of whaling around Spitsbergen, two companies – the Dutch Northern Company, and the English Muscovy Company – emerged as the leading players in the Arctic whaling industry. The governments of England and the Dutch Republic had granted these companies monopolies on whaling operations, but they were resented by merchants and mariners who preferred to operate independently. After around 1625, as bowhead whales dispersed amid warming temperatures, competition between Dutch whalers devolved into piracy. Many conflicts involved whalers who sailed either for the Northern Company or for themselves, although even some Company whalers hid the best hunting grounds from one another. In these circumstances, the governing body of the Dutch Republic rescinded the monopoly of the Northern Company in 1642.
From the beginning, competition between English whalers assumed an even more brutal character. The Muscovy Company took an uncompromising stance towards English interlopers, who responded in turn. In 1626, for example, whalers aboard independently-owned vessels destroyed the Company’s station at Horn Sound, Spitsbergen, after they had been harassed by Company ships. Not surprisingly, petitions submitted to the English Standing Council for Trade in 1652 reveal that small groups of English merchants also sought to overturn the monopoly of the Muscovy Company. Individual merchants insisted that the Company could not adequately “fish” the territories over which it held a monopoly. The Company responded that whalers in the employ of those merchants had interfered with the activities of its sailors and stolen whales they had killed.
Warming temperatures that reduced the extent of pack ice and encouraged whales to disperse may well have encouraged competition and conflict between whalers belonging to the same nationality. Bizarrely, the whaling industry also responded to fluctuations in the supply of rape, linseed and hemp oils, which were less smelly substitutes to whale oil for fueling lamps or manufacturing soap, leather, or wax. Temperature and precipitation extremes that reduced the supply of vegetable oils naturally also increased the price of whale oils in the Dutch and English economies, and thereby the profitability of whaling. In the context of the Little Ice Age, the 1630s in particular were relatively warm across the Northern Hemisphere. The trusty Allen-Unger commodity database tells us that the price of linseed oil in Augsburg, for example, dropped sharply as average annual temperatures increased. Even the price of lamp oil – which would have also registered the price of whale oil – fell modestly in the same period. Could whalers in the 1630s and 1640s have vied with monopolistic companies just climate change both reduced the supply of their resource and increased its profitability?
We can sketch these relationships by mixing and matching different statistics from natural and textual archives. Detailed qualitative accounts written by whalers, however, reveal that climate influenced conflict in more complicated ways during the first decade of the Svalbard whaling industry. In that decade, whalers from several European nations – most importantly England and the Dutch Republic – employed experienced Basque whalers to kill bowhead whales, strip their blubber, and boil the blubber on the coast. Whalers would deploy boats from a mothership to kill small groups of whales. They would then establish temporary settlements on the coast to turn the blubber into oil that could be loaded into barrels and returned to the ship.
These techniques forced whalers from different nations to rove along the coast of Spitsbergen, which made it likely that they would encounter one another. Initially, the Muscovy Company falsely claimed that English explorers had found Spitsbergen, which meant that it alone had the right to hunt for whales off the island. The Dutch – who had actually discovered the island – insisted that whalers from all European nations should be allowed to fish off its coast. In 1613, a Dutch expedition under Willem van Muyden, the legendary “First Whaleman” of the Republic, reached Spitsbergen in late May and found the coast blocked by ice. After only two weeks, the retreating ice let his whalers enter a bay roughly halfway down the island, but a better-armed English fleet quickly spotted them. In subsequent weeks, the English harassed the Dutch whalers and stole much of their equipment and whale commodities. Yet the Dutch returned with naval escorts in 1614. After the English seized a Dutch ship in 1617, the Dutch arrived with overwhelming force in 1618 and killed several English whalers.
The worst skirmishes between Dutch and English whalers raged in years that were relatively warm across the Arctic and probably around Svalbard, despite the generally cooler climate of the early seventeenth century. In cold years, sea ice could have kept whalers working for different companies from lingering on the coast, where tensions simmered and eventually erupted into bloodshed. In any case, the Muscovy Company and the Northern Company eventually agreed to occupy different parts of Spitsbergen. The Dutch would claim the northwestern tip, where they established the major, fortified settlement of Smeerenburg: “blubber town.” The English, meanwhile, took the rest. The Dutch eventually benefited from being closer to the edge of the summer pack ice, where there were more whales to hunt.
Hostilities between the English and the Dutch in the volatile first decades of the Svalbard whaling industry convinced the Northern Company to keep a skeleton crew at Smeerenburg and nearby Jan Mayen island during the winter. If they could survive, they would keep Company infrastructure safe from springtime raids and provide valuable information about the region’s winter weather. In 1633/34, two groups of Dutch whalers overwintered at Smeerenburg and Jan Mayen. Regional summer temperatures may have been warming at the time, but winter temperatures across the Arctic were cooling, and 1633/34 was particularly cold. The Smeerenburg group survived the frigid temperatures and killed enough caribou and Arctic foxes to hold off scurvy. The Jan Mayen whalers endured until the spring, but they could not catch enough game to survive the ravages of scurvy. In 1634/35, the Northern Company tried again. This time, both groups died from scurvy, and the Smeerenburg whalers did not even make it to winter. Violent competition between whaling companies – plausibly influenced by warming summers – exposed whalers to a quirk in the climatic trends of the Little Ice Age in the Arctic: the big difference between summer and winter temperatures, relative to long-term averages.
Climate change also influenced hostilities between whalers by altering how easily they could reach the “battlefield” around Spitsbergen. In 1615, a year of typical chilliness during the Little Ice Age, the author of a Dutch whaling logbook reported that sea ice on June 7th blocked the crew’s progress towards Svalbard. The crew spotted a bowhead whale three days later, but ice kept them from pursuing. That evening, a storm rose just as they found themselves surrounded by sea ice. They tried to anchor themselves to an iceberg, but it shattered and would have destroyed their ship “had God not saved us.” The few surviving logbooks written by Dutch whalers also record trouble with ice in the warmer 1630s, yet it surely would have been harder to reach Svalbard and compete with English whalers in the first decade of the Arctic whaling industry.
Beginning in 1652, the Dutch Republic and England also embarked on hostilities in the North Sea region that would endure, with interruptions, until the Dutch invasion that launched the Glorious Revolution of 1688. During the three Anglo-Dutch Wars that raged in these decades, English and Dutch ordinance kept whalers from sailing to the Arctic or constructing new ships and equipment for the whaling industry. Sailors who might have served aboard whaling ships were urgently needed to crew the warships of the English and Dutch fleets. Many whalers also served as privateers, raiding merchant ships and convoys and then surrendering a share of the profits to their governments. Any whalers who set sail for the Arctic risked losing everything if discovered.
As I have written elsewhere, a cooling climate in the second half of the seventeenth century profoundly influenced naval hostilities between the English and Dutch fleets. By altering the frequency of easterly and westerly winds in the North Sea, it helped the English claim victory in the First Anglo-Dutch War but aided the Dutch in the Second and Third Anglo-Dutch Wars, as well as the Glorious Revolution. It probably shortened the First Anglo-Dutch War (1652-54) but lengthened the third war (1672-74). That, in turn, would mean that the manifestations of global climate change in the North Sea affected the opportunities for whalers to engage in hostilities in the Arctic.
After 1650, the character of hostilities between Arctic whalers changed dramatically. Cooling summer temperatures brought thick ice into the harbors of Spitsbergen, while the depletion of the bowhead whale population may have worsened the prospects of whaling near land. Whalers had to hunt further and further from the shore, and started processing their whales at sea. They abandoned settlements along the coast of Spitsbergen, which soon fell into ruin. Violence between whalers now took place exclusively at sea. The evidence is spotty, but privateers seem to have hunted whalers in the final decades of the seventeenth century. In 1692, Henry Greenhill, commissioner of the English navy at Plymouth, reported that two “Greenland Prizes” – whaling vessels captured off Spitsbergen – had been brought into harbor. Since England had allied with the Dutch Republic against France, these ships were probably French in origin.
The history of climate change, whaling, and violence in and around Svalbard during the seventeenth century is above all complicated, filled with surprising twists and turns. Climate change may have occasionally provoked violence, but it probably did so by reducing, rather than increasing, the accessibility of bowhead whales to whalers. More importantly and more certainly, it altered the character of confrontations between whalers in the far north. Moreover, its manifestations thousands of kilometers from the Arctic ended up having important consequences for hostilities in and around Svalbard.
These intricate relationships in the distant past should give us pause as we contemplate the warmer future in the Arctic. Global warming may indeed set the stage for war in the far north, but we have no way of knowing for sure. It is equally likely that climate change will provoke human responses that are hard to guess at present. In this case, we cannot use the past to predict the future, but we can draw on it to ask more insightful questions in the present.
Selected Works Cited:
Degroot, Dagomar. “Exploring the North in a Changing Climate: The Little Ice Age and the Journals of Henry Hudson, 1607-1611.” Journal of Northern Studies 9:1 (2015): 69-91.
Degroot, Dagomar. “Testing the Limits of Climate History: The Quest for a Northeast Passage During the Little Ice Age, 1594-1597.” Journal of Interdisciplinary History XLV:4 (Spring 2015): 459-484.
Degroot, Dagomar. “‘Never such weather known in these seas:’ Climatic Fluctuations and the Anglo-Dutch Wars of the Seventeenth Century, 1652–1674.” Environment and History 20.2 (May 2014): 239-273.
Hacquebord, Louwrens. De Noordse Compagnie (1614-1642): Opkomst, Bloei en Ondergang. Zutphen: Walburg Pers, 2014.
Hacquebord, Louwrens. “The hunting of the Greenland right whale in Svalbard, its interaction with climate and its impact on the marine ecosystem.” Polar Research 18:2 (1999): 375-382.
Hacquebord, Louwrens and Jurjen R. Leinenga. “The ecology of Greenland whale in relation to whaling and climate change in 17th and 18th centuries.” Tijdschrift voor Geschiendenis 107 (1994): 415–438.
Hacquebord, Louwrens, Frits Steenhuisen and Huib Waterbolk. “English and Dutch Whaling Trade and Whaling Stations in Spitsbergen (Svalbard) before 1660.” International Journal of Maritime History 15:2 (2003): 117-134.
Laist, David W. North Atlantic Right Whales: From Hunted Leviathan to Conservation Icon. Washington, DC: Johns Hopkins University Press, 2017.
McKaya, Nicholas P. and Darrell S. Kaufman. "An extended Arctic proxy temperature database for the past 2,000 years." Scientific Data (2014). doi: 10.1038/sdata.2014.26.
Dr. Bathsheba Demuth, Brown University.
The Greenlandic coast. Source: TheBrockenInaGlory, Wikimedia Commons, 2005, commons.wikimedia.org/wiki/File:Greenland_coast.JPG
In the year 1001 CE, Leif Erikson made landfall in Greenland, and traded with people who “in their purchases preferred red cloth; in exchange they had furs to give.” The Vikings called these people Skraelings. Present-day archeologists and historians call them the Thule. At its height, Thule civilization spread from its origins along the Bering Strait across the Canadian Arctic and into to Greenland. The ancestors of today’s Inuit and Inupiat, the Thule accomplished what Erikson and subsequent generations of Europeans never managed: living in the high Arctic without supplies of food, technology, and fuel from more temperate climates.
The Thule left archeological evidence of a technologically sophisticated, vigorous people. They invented the umiak, an open walrus-hide boat so large that it was sometimes equipped with a sail. These boats, when used alongside small, nimble kayaks, made the Thule formidable marine-mammal hunters. On land, they harnessed dogs to sleds and built homes half-underground, insulated by earth and beamed with whale bones.
People did inhabit the high North American Arctic before the Thule. Their immediate predecessors, called the Dorset by archeologists, were expert carvers, and there are signs of other cultures that date back at least five thousand years. But the Thule appear to have been a particularly robust society, one that inhabited thousands of challenging Arctic miles. Eventually, they even traded with Europeans for metal tools, sending walrus ivory as far abroad as Venice.
Thule migration routes from the Bering Strait east. Map credit: anthropology.uwaterloo.ca/ArcticArchStuff
In the twentieth century, many archeologists linked the success of the Thule to the climate. In this view, rapid Thule expansion coincided with the Medieval Warm Period in the years between 1000 and 1300. The Thule were expert whalers, especially of bowhead whales. This slow species makes for good prey. Their 100-ton bodies can be fifty percent fat by volume, giving people ample calories to eat and burn through long winters. With the slight increase in temperature during the Medieval Warm Period, the theory went, the range of the bowhead whale expanded across newly ice-free waters. Atlantic and Pacific bowhead populations eventually met in the Arctic Ocean north of Canada, offering an uninterrupted banquet of blubber to hunters.
The Thule, in this view, were simply whale hunters who followed the migration of their prey in a warming climate. Environmental conditions, not a sophisticated culture, was the key explanation for their success. Emphasizing climate as the cause of migration and social success reduced the achievements of the Thule, essentially, to those of their prey.
However, twenty-first century evidence is changing this account of Thule migration. In 2000, Robert McGhee questioned the validity of the radiocarbon dates that helped establish Thule expansion as an eleventh-century phenomenon. He proposed the 1200s as the earliest date of migration. Then, genetic tests by marine biologists showed that Atlantic and Pacific bowhead whales did not mix their populations during the Medieval Warm Period, meaning that there was a substantial gap in whaling possibilities on the Arctic coast.
Something more complicated than just following the blubber drove the Thule eastward. McGhee speculated that communities moved for iron, which is short supply in the Arctic. Thule hunters learned from the Dorset people of a deposit left by the Cape York meteorite. They colonized huge territories to secure their access to this precious resource from outer space. Other specialists theorized that population pressure, overhunting, or warfare led the Thule to migrate east.
Thule archeological site, with whalebone beams among flooring stones. Photo credit: anthropology.uwaterloo.ca/ArcticArchStuf
The ongoing work of Canadian archeologists T. Max Friesen and Charles D. Arnold seems to confirm that we must look beyond simple climatic explanations for the Thule expansion. Working on Beaufort Sea and Amundsen Gulf sites, the pair established that there was no definitive Thule occupation in this part of the western Arctic prior to the thirteenth century. Because any Thule migrants would have had to pass through these points as they moved east, their research indicates that the Thule civilization was only beginning its continental spread around the year 1200, well into the period of warming. The climate may have helped the Thule quickly spread toward Greenland, but the onset of the Medieval Warm Period did not automatically draw people eastward.
Moreover, the work of other archeologists on the Melville Peninsula, along Baffin Bay, indicates that the Mediaeval Warm Period was not always so warm. Some areas of the Arctic saw slight temperature increases, but in general the millennium was cooler than those past. In places, the effects of the so-called Little Ice Age began a century or two before they were evident across the globe, meaning the Thule adapted not to a warmer Arctic, but a colder one. This cooling was more apparent in the west, where the team found fewer Thule sites but also more stability, both in the climate and the record of human occupation. To the east of the Melville Peninsula, where temperatures did warm, the climate was also more variable – adding a new set of complexities to social and economic life. The move into the central Arctic, therefore, reflected forces other than climate.
Beginning in the fifteenth century, Thule culture fragmented, specialized, and emerged eventually as distinct contemporary Inuit and Inupiat groups. The Little Ice Age is often the reason given for the disintegration of Thule civilization in the fifteenth century. Yet, the work by Finkelstein, Ross, and Adams indicates that, while the Thule abandoned some sites due to cooling trends, this did not hold in all cases. Other causes, including increased contact with Europeans and their infectious diseases, might have had more to do with the disintegration in some locations.
Overall, the new vision of the Thule prominence in the Arctic makes their rise shorter, but even more impressive. And if the Thule began their migration only in 1200, it seems unlikely they spread east simply to find iron. This would have required only smaller-scale movements to precise locations. Instead, the Thule developed a thriving, intricate network of settlements across the Arctic. For Friesen and Arnold, this is evidence that the Thule expanded in order to recreate the ideological and economic lives that they had enjoyed in their origins along the Bering Strait. And in just a century they did, not only by inhabiting land from the Bering Strait to Greenland, but through explorations to the northern edges of the continent.
All of this also helps us reinterpret a well-known tale from the Viking exploration of the Arctic. When Leif Erikson’s sister Freydis frightened off a band of Skraelingar in the early eleventh century by striking “her breast with the naked sword” of a fallen Viking, she was likely not fighting the Thule, as scholars have assumed. Perhaps it was the Dorset people that “were frightened, and rushed off in their boats.” The Thule, at least, were likely still a century away from the eastern Canadian coastline. They were not easily daunted either by a shifting climate or by Viking weapons.
Quotes from the Saga of Erik the Red, English translation by J. Sephton, can be found here: http://www.sagadb.org/eiriks_saga_rauda.en
Friesen, T. Max and Charles D. Arnold. “The Timing of the Thule Migration: New Dates from the Western Canadian Arctic,” American Antiquity 73 (2008): 527-538.
Finkelstein, S.A., J.M Ross, and J.K Adams. “Spatiotemporal Variability in Arctic Climates of the Past Millennium: Implications for the Study of Thule Culture on Melville Peninsula, Nunavut,” Arctic Antarctic, and Apline Research 41 (200): 442-454.
McGhee, Robert. “Radio Carbon Dating and the Timing of the Thule Migration,” in Appelit, M. Berglund, J, and Gullov, H.C. eds. Identities and Cultural Contacts in The Arctic: Proceedings from a Conference at the Danish National Museum. Copenhagen (2000): 181-191.
Morrison, David. “The Earliest Thule Migration.” Canadian Journal of Archaeology 22( 1999): 139-156.
Betts, Matthew, and T. Max Friesen, “Quantifying Hunter-Gatherer Intensification: A Zooarchaeological Case Study form Arctic Canada,” Journal of Anthropological Archaeology 23 (2004): 357-384.
Dyke, Arthur S., James Hooper, and James M. Savelle. “A History of Sea Ice in the Canadian Arctic Archipelago based on Postglacial Remains of the Bowhead Whale (Balaena mysticetus)”, Arctic 49 (1996): 235-255.
Park, Robert W. “The Dorset-Thule Succession Revisited,” in Appelit, M. Berglund, J, and Gullov, H.C. eds. Identities and Cultural Contacts in the Arctic: Proceedings from a Conference at the Danish National Museum. Copenhagen (2000): 192-205.
Last year might have been the hottest year ever recorded by our instruments. Average global temperatures were at least 0.27° C warmer than the average between 1981 and 2010, which was in turn up from the preindustrial norm. Overall, the past 17 years have been very warm, and since 2002 temperatures have been consistently well above the 1981-2010 average. However, that consistency is not clearly reflected in Arctic sea ice trends. In fact, the winter extent of Arctic sea ice has expanded in the last two years, seemingly defying projections of its imminent collapse.
Arctic sea ice is extremely complex and comes in many forms that respond more or less aggressively to seasonal changes and temperature anomalies. Currents, wind patterns, and even subtle differences in Earth’s gravitation also influence sea ice extent, although temperature usually plays a dominant role. As a result, Arctic sea ice coverage rises in winter and falls in summer. Its minimum and maximum yearly extent reflect shifts in average annual temperature, and in turn climate change.
In the winter of 2010/11, Arctic sea ice reached its lowest-recorded extent (above). Satellite data reveals that, in December 2010, average Arctic sea ice covered just 12 million square kilometers. While that may sound like a lot, it is some 1.35 million square kilometers below the 1979-2000 average, and 270,000 square kilometers below the previous record low (set in 2006).
The sharp decline in Arctic sea ice coincided with very high global temperatures. In fact, scientists are still determining whether 2014 was actually warmer than 2010. In the wake of the winter of 2010/11, it seemed as though even the direst projections of Arctic sea ice decline had been too optimistic. Perhaps a threshold had been crossed, a tipping point had been reached, and Arctic sea ice would soon vanish.
However, since the winter 2010/11 Arctic sea ice extent has haltingly recovered. Satellite maps demonstrate that Arctic sea ice currently covers 12.52 million square kilometers, about 520,000 square kilometers more than the 2010/11 maximum (above). The greatest change relative to 2010/11 is in the Canadian Arctic and Subarctic, where the Hudson and Baffin Bays are now completely covered with ice.
If Arctic warming has persisted since 2010, why has Arctic sea ice recovered? One possible explanation lies in the recent history of the Arctic Oscillation (AO), a band of winds that circle the Arctic in a counter clockwise direction. When the AO is in a positive phase, its winds move quickly, tightly sealing frigid air in the Arctic. When it is in a negative phase, its winds move more slowly and the band is distorted, allowing Arctic air to descend towards lower latitudes. There appears to be a correlation between a negative AO and reductions in Arctic sea ice extent. The AO, which was in a strongly negative phase in 2010, is now apparently in a weakly positive setting.
Recent research also suggests that Arctic sea ice has a very low “memory” of previous trends. If, for example, Arctic sea ice extent is very low in September, winter heat loss is high, encouraging the formation of more sea ice. Such processes explain high year-to-year fluctuations in sea ice, yet they do not preclude long-term trends.
The apparent recovery of Arctic Sea Ice therefore does not counter long-term developments in either regional sea ice decline or global warming. Sea ice extent in December was still 540,000 kilometers below the 1981-2010 average, which means that sea ice coverage in the Arctic is still declining by 3.4%/decade. Most model simulations still project an accelerating decline in Arctic sea ice extent, even in optimistic scenarios in which our civilizations sharply reduce their greenhouse gas emissions (above).
Model simulations, scientific proxy data, and documentary evidence assessed by interdisciplinary scholars can contextualize sea ice in the modern Arctic in light of the distant past. My own recent research suggests that sea ice extent in the Arctic north of Europe during December 2014 is not dissimilar to what was encountered by European polar explorers during summer expeditions at the height of the Little Ice Age. This reflects climate change on a remarkable scale, given the vast annual difference between summer and winter sea ice coverage in the Far North.
For example, I traced sea ice recorded by Henry Hudson and his crew, during their first Arctic expedition. In the above map, the outbound journey is depicted with a black solid line, while the return journey portrayed in a blue, dashed line. The part of the voyage in which ice was sighted is in white; a solid white line for the outbound journey, and a dashed line for the return. Compare the summer sea ice sighted in the Hudson journey with the edge of winter sea ice today (the second map provided in this article).
Ultimately, Arctic sea ice fluctuates from year to year in ways that can temporarily mask gradual climate change. The world is warming, and the Arctic is warming faster than anywhere else. It is important to keep an eye on the recent recovery in Arctic sea ice, but all indications are that it is just a momentary reprieve in a very worrisome trend.