Projected climate change impacts in the four regions of the Arctic

Published: February 9, 2010, 5:58 pm

Updated: May 7, 2012, 5:42 pm

Topics:

International Environmental Issues (main) Climate Change (main)

This is Section 18.3 of the Arctic Climate Impact Assessment. Lead Author: Gunter Weller; Contributing Authors: Elizabeth Bush,Terry V. Callaghan, Robert Corell, Shari Fox, Christopher Furgal, Alf Håkon Hoel, Henry Huntington, Erland Källén, Vladimir M. Kattsov, David R. Klein, Harald Loeng, Marybeth Long Martello, Michael MacCracken, Mark Nuttall,Terry D. Prowse, Lars-Otto Reiersen, James D. Reist, Aapo Tanskanen, John E.Walsh, Betsy Weatherhead, Frederick J.Wrona

This section examines impacts within a more regional setting. A spatial division is necessary because the Arctic is very large and different regions are likely to experience patterns of climate change in the coming decades that are significantly different. Different regions of the Arctic are also distinguished by different social, economic, and political systems, which will mediate the impacts of and responses to climate change. These distinctions are captured broadly by the four regions defined in this assessment (see Fig. 18.6).

Differences in large-scale weather and climate-shaping factors were primary considerations in selecting the four regions. Observations also indicate that the climate is presently changing quite differently in each of these regions, and even within them, especially where there are pronounced variations in terrain, such as mountains versus coastal plains. There are also large north–south gradients in climate variability within each region. The scale was thought to be roughly appropriate given that a larger number of smaller regions would not have been practical for this assessment, or compatible with a focus at the circumpolar level.

Region 1 includes East Greenland, northern Scandinavia, and northwestern Russia, as well as the North Atlantic with the Norwegian, Greenland, and Barents Seas. This region is projected to experience similar types of changes because the entire area is under the influence of North Atlantic atmospheric and oceanic conditions, particularly the Icelandic Low.

Region 2 includes Central Siberia, from the Urals to Chukotka, and the Barents, Laptev, and East Siberian Seas. This region represents the coldest part of the Arctic and is under the influence of the Siberian high-pressure system during winter.

Region 3 includes Chukotka, Alaska, the western Canadian Arctic to the Mackenzie River, and the Bering, Chukchi, and Beaufort Seas. This region is largely under the influence of North Pacific atmospheric and oceanic processes and the Aleutian Low.

Region 4 includes the central and eastern Canadian Arctic east of the Mackenzie River, the Queen Elizabeth Islands south to Hudson Bay, and the Labrador Sea, Davis Strait, and West Greenland. The region’s weather systems are connected to large-scale North American and western North Atlantic weather patterns.

Figure 18.6. The four regions of the Arctic Climate Impact Assessment. Source: IASC

Major impacts due to observed and projected climate change for each of the four regions are summarized in sections 18.3.1 to 18.3.4. Details, including relevant references and publications on earlier impact assessments in the four regions, can be found in the preceding 17 chapters. The previous regional impact assessments were useful source material and laid a critical foundation for the ACIA. Some impacts apply to more than one or to all of the regions; such impacts are described in section 18.2 and are not necessarily listed separately for each region.

While the importance of providing information at the regional level has been emphasized here, the focus of the ACIA was at the circumpolar scale. The following sections attempt to synthesize significant findings for each of the four regions where these have been provided by the relevant chapters of the assessment. In some cases, the evaluated literature did not support a very extensive assessment of the nature of changes in the four regions.

Table 18.9 summarizes the key consequences of climate change on the environment, the economy, and people’s lives in each of the four regions. The following sections provide additional information by region. Projections of climate change for each region are based on output from the five ACIA-designated climate models.

Table 18.9. Key consequences of climate change on the environment, the economy, and on people’s lives in the four ACIA regions. Unless otherwise stated these key consequences are considered likely to occur.

	Environment	Economy	People’s lives
Region 1 Eastern Greenland, North Atlantic, northern Scandinavia, northwestern Russia	Northward shifts in the distribution ranges of plant and animal species (terrestrial, freshwater, and marine) Many tundra areas disappear from the mainland, except in arctic Russia where bog growth prevents forest development Carbon storage increases and albedo decreases, but less so than in other regions	Change in the location of North Atlantic and Arctic fisheries due to warmer waters and change in yields of many commercial fish stocks Improved access to oil, gas, and mineral resources in presently ice-covered waters and adjacent land areas Rising sea level and more storm surges affect coastal facilities	Reduced and changing snow cover, affecting reindeer herding and hunted wildlife Traditional harvest of animals is riskier and less predictable Emergence of zoonotic diseases as a threat to human health Increased outdoor leisure and recreational opportunity, plus lower heating costs
Region 2 Siberia	Northward shifts in the distribution ranges of plant and animal species (terrestrial, freshwater, and marine) Changing forest character due to warmer climate and permafrost thawing, with possibly greater fire and pest threats Tundra changing to shrub and forest, but northern tundra extension limited by the ocean Increased river discharge, affecting sediment and nutrient fluxes	Reopening of the Northern Sea Route (Northeast Passage), due to reduced extent and duration of sea ice, providing new economic possibilities, and also increased pollution risks (tankers) Improved access to oil, gas, and mineral resources in presently ice-covered waters and adjacent land areas Rising sea level and more storm surges affect coastal facilities	Permafrost thawing, causing serious damage to buildings in Siberian cities and to houses and facilities in villages Traditional harvest of animals is riskier and less predictable Emergence of zoonotic diseases as a threat to human health Lower heating costs
Region 3 Chukotka, Bering Sea, Alaska, western Canadian Arctic	Northward shifts in the distribution ranges of plant and animal species (terrestrial, freshwater, and marine) Forest disruption due to warming and increased pest outbreaks Reduced sea ice and general warming, disrupting polar bears, marine mammals, and other wildlife Low-lying coastal areas more frequently inundated by storm surges and sea-level rise	Damage to infrastructure due to thawing permafrost Improved access to oil, gas, and mineral resources in presently ice-covered waters and adjacent land areas Change in recruitment, growth rates, abundance, and distribution of Bering Sea fish due to warmer waters Rising sea level and storm surges, affect coastal facilities	Retreating sea ice and earlier snowmelt, altering traditional lifestyle patterns and food security, increasing risks taken by hunters, further stressing nutritional status Coastal erosion and flooding forcing relocation of villages Emergence of zoonotic diseases as a threat to human health Increased outdoor leisure and recreational opportunity, plus lower heating costs
Region 4 Central and Eastern Canadian Arctic, Labrador Sea, Davis Strait, West Greenland	Thawing of warm permafrost and reduced river and lake ice, changing hydrological regimes Northward shifts in the distribution ranges of plant and animal species (terrestrial, freshwater, and marine) High-arctic polar desert replaced by tundra in some areas, leading to potential large carbon gains Increased melting of the Greenland Ice Sheet, changing the coastal environment Decreasing sea-ice extent; threatening the extinction of polar bears	Potential increased shipping in the Northwest Passage as sea ice retreats, providing economic incentives such as cheaper transport of goods, but also increasing pollution and oil-spill risks Shorter operating season for ice and snow roads Changes in marine and freshwater fisheries with impacts on tourism and local economic development Rising sea level and storm surges affect coastal facilities	Traditional lifestyles and survival of indigenous hunting culture threatened by retreating sea ice and changing environment Health impacts via stresses on food security and safety of travel conditions Emergence of zoonotic diseases as a threat to human health Increased outdoor leisure and recreational opportunity, plus lower heating costs

Region 1 (18.3.1)

Changes in climate (18.3.1.1)

Most of Region 1 experienced a modest increase in mean annual temperature (about 1 ºC) between 1954 and 2003, with slightly higher winter temperature increases over this period, except for Iceland, the Faroe Islands, and southern Greenland, where there has been some cooling (see Fig. 18.2 for regional details). From 1990 to 2000, greater warming was observed in northern Scandinavia, including Iceland, Svalbard, and East Greenland, but cooling was observed in other areas such as the Kola Peninsula.

Model projections (see Fig. 18.5 for regional details) indicate that this region is likely to experience additional increases in mean annual temperature of 2 to 3 ºC in Scandinavia and East Greenland and up to 3 to 5 ºC in northwestern Russia by the late 21st century. Although changes in atmospheric and oceanic circulation contributed to some cooling of the region during the 20th century, warming has occurred in recent decades and is projected to dominate throughout the 21st century. Precipitation has increased slightly and is projected to increase further by up to about 10% by the end of the century.

Impacts on the environment (18.3.1.2)

The geography and environment of Region 1 are dominated by the North Atlantic Ocean, which has extensive connections with the Arctic Ocean via the Norwegian, Greenland, and Barents Seas. The North Atlantic Ocean separates Greenland in the west from the Fennoscandian, European, and western Russian landmasses in the east. Relatively isolated islands of Iceland, the Faroe Islands, and the Svalbard and Franz Josef archipelagos span the low to high arctic latitudes. The land areas are characterized by a north–south climatic contrast between low-arctic environments in the south isolated by ocean from the high-arctic environments of the highlatitude islands, and by an east–west climatic contrast between the Scandinavian landmass, which is uncharacteristically warm for its latitude, and East Greenland in the west of the region, which is heavily glaciated. The continuous south–north land corridors for movement of terrestrial and freshwater species and people found in Region 2, for example, are missing.

The Greenland, Iceland, Norwegian, and Barents Seas constitute a major part of this region. This vast oceanic area is influenced by the inflow of relatively warm Atlantic water, which enters along the coast of Norway and is the most northward branch of the Gulf Stream. Variability in the volume of this inflow, as experienced in the past and as projected by models for the future due to global climate change, is expected to have major consequences for the physical and biological regimes of the region. Sea surface temperature is expected to increase, and the Barents Sea is expected to be totally ice free in summer by 2080. Changes in the distribution of important fish stocks are expected to occur. Past integrative impact assessments of climate change in this region include publications by Lange et al. for the Barents Sea.

The arctic seas in Region 1 are projected to experience a temperature increase that will lead to a decrease in seaice cover, especially in summer, as well as earlier ice melt and later freeze-up. Unless compensated for by an increase in low-level cloudiness, decreases in sea-ice cover would reduce the overall planetary albedo of the region and provide a positive feedback to the global climate. The reduction in sea ice is likely to enhance primary productivity, lead to increases in zooplankton production, and possibly to increased fisheries production. Such changes would also lead to decreased natural habitat for polar bears (Ursus maritimus) and ringed seals (Phoca hispida) to an extent that is likely to threaten the survival of their populations in this region. Conversely, more open water is expected to favor some whale and seabird species. Biodiversity is high in Region 1: around 6000 marine and terrestrial species have been recorded for Svalbard and around 7200 species have been recorded for 22705 km2 between 68º and 70º N in northern Finland. The European Arctic and subarctic are important breeding areas for many bird species overwintering in more temperate regions. Excluding the Russian Arctic, over 43% of the European bird species pool occurs in Region 1.

Observations indicate very variable climate trends and ecological responses to them in Region 1 (see Chapter 7). Treelines in northern Sweden increased in altitude by up to 40 m during the first part of the 20th century, and a further 20 m during the warming of the past 40 years, giving recent rates of treeline increase of 0.5 m/yr and 40 m/ºC. In northern Finland, the pine treeline is increasing in altitude and density, and in the Polar Ural Mountains, treeline has advanced. However, there is little evidence of a northward shift of the latitudinal treeline west of the Polar Ural Mountains. Unexpectedly, evidence shows a southward movement of the treeline in parts of the forest tundra of the Russian European Arctic, a change that appears to be associated with localized pollution, deforestation, agriculture, and the growth of bogs leading to tree death.

In the Faroe Islands, there has been a lowering of the alpine altitudinal treeline in response to a cooling of 0.25 ºC during the past 50 years. In some areas of Finland and northern Sweden, there is evidence of an increase in rapidly changing warm and cold episodes in winter that lead to increasing bud damage in birch. Recent warming in northern Sweden and Finland has led to a reduction in the extent of discontinuous permafrost in mires and a change in vegetation resulting in increased CH4 flux to the atmosphere. Recent warm winters have resulted in unusual conditions (causing ice layers in the snow) unfavorable for reindeer and wildlife, and leading to an absence of lemming population peaks, and on Svalbard, a decline in wild reindeer (Rangifer tarandus platyrhynchus) through decreases in the availability of food resources. Changes in animal populations also include reductions in arctic fox (Alopex lagopus) and snowy owl (Nyctea scandiaca) (as well as several other bird species) populations on mainland Fennoscandia but a northward migration of larger butterflies and moths, the larvae of some being defoliators of trees and shrubs. Moose (Alces alces), red fox (Vulpes vulpes), and the invasive species mink (Mustela vison) are increasing in the east of the region and muskoxen (Ovibos moschatus), wolves, and pinkfooted (Anser brachyrhynchus) and barnacle geese (Branta leucopsis) are increasing in northeast Greenland.

If warming occurs as projected, the deciduous mountain birch forest that forms much of the present treeline in the region, the boreal conifer forest and woodland, and the arctic and alpine tundra are very likely to begin shifting northward and upward in altitude. The potential for vegetation change within the region is perhaps greatest in northern Scandinavia, where large shifts occurred in the early Holocene in response to warming. Here, pine forest is projected to invade the lower belt of mountain birch forest. The birch treeline is projected to move upward and northward, displacing shrub tundra vegetation, which in turn is projected to displace alpine tundra. Alpine species in the north are expected to be the most threatened because there is no suitable geographic area for them to shift toward in order to avoid being lost from the Fennoscandian mainland. In Iceland, a warmer climate is likely to facilitate natural regeneration of the heavily degraded native birch woodland as well as aid current and future afforestation efforts (Chapter 14).

Model projections suggest that arctic tundra will be displaced totally from the mainland by the end of the 21st century (Fig. 18.1), although in practice, the bogs of the western Russian European Arctic may prevent forests from reaching the coast. Model projections of change from tundra to taiga between 1960 and 2080 (5.0%), and of change from polar desert to tundra (4.2%), are the lowest of any of the four ACIA regions because of the lack of tundra areas and the separation of the high Arctic from the subarctic.

While the climate is changing, local forest damage is projected to occur as a result of winters that are warmer than normal.Warmer winters are likely to lead to an increase in insect damage to forests and decreases in populations of animals such as lemmings and voles that depend upon particular snow conditions for survival. These changes, in turn, are likely to cause decreases in populations of many existing bird species and other animals, with the most severe effects on carnivores, such as Arctic foxes, and raptors, such as snowy owls. Heathland and wetland areas are likely to be partially invaded by grasses, shrubs, and trees, and mosses and lichens are expected to decrease in extent. Unlike other arctic areas, fire is not likely to play a major role in controlling vegetation dynamics. Any changes in land-use patterns, including increased agriculture and domestic stock production in a warmer climate, will encroach on wildlife habitats and further threaten large carnivores.

Some areas in this region, such as East Greenland and the Faroe Islands, have experienced recent cooling, and future warming is expected to reverse the present downward vegetation shifts in the mountains of the Faroe Islands. The island settings in this region, particularly those of Greenland, Svalbard, Franz Josef Land, and Novaya Zemlya, are likely to delay the arrival of immigrant species and substantial change other than expansion and increased growth of some current species.

Changes in arctic ecosystems will not only have local consequences but will also have impacts at a global level because of the many linkages between the Arctic and other regions further south. For example, several hundreds of millions of birds migrate to the Arctic each year and their success in the Arctic determines their populations at lower latitudes. As previously noted, excluding the Russian Arctic, over 43% of the European bird species pool is found in Region 1. Changes in their wintering areas far south of the Arctic also play an important part in the ecology of migratory birds and there are many important stop-over sites and overwintering grounds in Europe. Birds that are already suffering major declines in the region include lesser white-fronted goose (Anser erythropus) and shore lark (Eremophila alpestris) that have almost become extinct in Fennoscandia, and snowy owls. In contrast, some southern bird species have become established. Examples include blue tit (Parus caeruleus) and greenfinch (Carduelis chloris).

Changes in carbon storage and release from ecosystems also have potential global consequences. Christensen et al. estimated that CH4 emissions have increased from between 1.8 and 2.2 mg CH4/m2/hr to between 2.7 and 3.0 mg CH4/m2/hr over the past 30 years in northern Sweden, as a result of permafrost thaw and vegetation change. Terrestrial carbon storage and net primary production are projected to increase, and albedo to decrease, but less than in any other region due to the ocean barriers and general lack of tundra: there is a transition from subarctic to high Arctic separated by seas where the mid-arctic tundra should be.

Impacts on the economy (18.3.1.3)

Region 1 has abundant renewable and non-renewable resources (timber, fish, ore, oil, and natural gas). The highly productive marine life makes this region one of the most productive fishing grounds in the circumpolar North. Higher ocean temperatures are likely to cause shifts in the distribution of some fish species, as well as changes in the timing of their migration, possible extension of their feeding areas, and increased growth rates. The occurrence of several “warm years” or “cold years” in a row, which is a sequence that could occur more frequently as a result of continuing global climate change, seems likely to lead to repercussions on the major fish stocks and, ultimately, the lucrative and productive fisheries in the region. Provided that the fluctuations in Atlantic inflow to the area are maintained, along with a general warming of the North Atlantic waters, it is likely that annual recruitment in herring (Clupea harengus) and Atlantic cod (Gadus morhua) will increase from current levels and will be about the same as the long-term average during the first two to three decades of the 21st century. This projection is also based on the assumption that harvest rates are kept at levels that maintain spawning stocks well above the level at which recruitment is impaired.

Impacts of climate change on the fisheries sector of the region’s economy are difficult to assess, however. A scenario of moderate warming could result in quite large positive changes in the catch of many species. A self-sustaining cod stock could be established in West Greenland waters through larval drift from Iceland. Past catches suggest that this could yield annual catches of about 300 000 t. Should that happen, it is estimated that catches of northern shrimp (Pandalus borealis) will decrease to around 30% of the present level, while those of snow crab and Greenland halibut (Reinhardtius hippoglossoides) might remain the same. Such a shift could approximately double the export earnings of the Greenlandic fishing industry, which roughly translates into the same amount as that presently paid by Denmark to subsidize the Greenland economy. Such dramatic changes are not expected in the Icelandic marine ecosystem. Nevertheless, there would be an overall gain through larger catches of demersal species such as cod, pelagic species like herring, and new fisheries of more southern species like mackerel (Scomber scombrus). On the other hand capelin (Mallotus villosus) catches would dwindle, both through diminished stock size and the necessity of conserving this very important forage fish for other species. Effective fisheries management will continue to play a key role both for Greenland and Iceland, however. Little can be said about possible changes under substantial climate warming because such a situation is outside any recorded experience.

Forestry and agriculture are important in Region 1; both have been affected by climate change in the past and impacts are likely to occur in the future. Longer growing seasons are likely to improve the growth of agricultural crops.While growth (net carbon assimilation) of forests and woodlands is likely to increase, this will not necessarily benefit the forestry industry as forest fires and pests will also increase. Forest pest outbreaks have been reported for the Russian part of the region, including the most extensive damage from the European pine sawfly (Neodiprion sertifer), which affected a number of areas, each covering more than 5000 ha. The annual number of insect outbreaks reported between 1989 and 1998 was 3.5 times higher than between 1956 and 1965. The mean annual intensity of forest damage increased two-fold between 1989 and 1998. Factors other than climate change are also important to forest-based economies. For example, while most of the region has seen modest growth in forestry, Russia has experienced a decline due to political and economic factors. These socio-economic problems are expected to be aggravated by global climate change, which in the short term will have negative effects on timber quality owing to fire and insect damage and on infrastructure and winter transport when permafrost thaws.

Impacts on people’s lives (18.3.1.4)

The prospects and opportunities of gaining access to important natural resources, both renewable and nonrenewable, have attracted a large number of people to Region 1. The relatively intense industrial activities, particularly on the Kola Peninsula, have resulted in population densities that are the highest throughout the circumpolar North. Impacts of climate change on terrestrial and marine ecosystems and implications for the availability of natural resources may lead to major changes in economic conditions and subsequent shifts in demography, societal structure, and cultural values.

Because they would affect food, fuel, and culture, changes in arctic ecosystems and their biota are particularly important to the peoples of the Arctic. Reindeer herding by the Saami and other indigenous peoples is an important economic and cultural activity and the people who herd reindeer are concerned about the impacts of climate change. Observations have shown that during autumn the weather in recent years has fluctuated between raining and freezing so that the ground surface has often been covered with an ice layer and reindeer in many areas have been unable to access the underlying lichen. These conditions are quite different from those in earlier years and have caused massive losses of reindeer in some years. Changes in snow conditions also pose problems. Since reindeer herding has become motorized, herders relying on snowmobiles have had to wait for the first snows to start herding. In some years, this has led to delays up to the middle of November. Also, the terrain has often been too difficult to travel over when the snow cover is light. Future changes in snow extent and condition have the potential to lead to major adverse consequences for reindeer herding and those aspects of health (physical, social, and mental) relating to the livelihood of reindeer herders.

The beneficial effects of a warmer climate on people’s recreational and leisure activities (camping, hiking, and other outdoor activities) should not be overlooked. Even relatively modest warming will improve people’s mental and physical health. A warmer climate is also likely to reduce heating costs.

Region 2 (18.3.2)

Changes in climate (18.3.2.1)

Region 2, which experiences the coldest conditions in the Arctic, has experienced an increase in mean annual temperature of about 1 to 3 ºC since 1954, and an increase of up to 3 to 5 ºC in winter (see Fig. 18.2 for regional details).

Models project that the mean annual temperature of Region 2 is likely to increase by a further 3 to 5 ºC by the late 21st century, and by up to 5 to 7 ºC in winter (see Fig. 18.5 for regional details). In the far north, winter warming of up to 9 ºC over the Arctic Ocean as a result of reduced sea-ice extent and thickness is projected. The summer warming over the land areas is projected to be 2 to 4 ºC by the end of the century, but there is likely to be very little change in summer over the Arctic Ocean.

Impacts on the environment (18.3.2.2)

This region has the largest continuous land mass, which stretches from the tropical regions to the high Arctic. It is very likely to experience major changes as the 1008 Arctic Climate Impact Assessment boreal forest expands northward, but tundra will persist, although with reduced area. For example, extensive tundra is likely to remain in the Taymir region but is likely to be displaced completely from the mainland in the Sakha region.

The large Siberian rivers draining into the Arctic Ocean are projected to experience major impacts. Projected increases in winter precipitation, and more importantly in precipitation minus evaporation, imply an increase in water availability for soil infiltration and runoff. The total projected increase in freshwater supplied to the Arctic Ocean could approach 15% by the latter decades of the 21st century. An increase in the supply of freshwater has potentially important implications for the stratification of the Arctic Ocean, for its sea-ice regime, and for its freshwater export to the North Atlantic. In addition, increased freshwater input into the coastal zone is likely to accelerate the degradation of coastal permafrost.

On land, the projected increase in precipitation is likely to lead to wetter soils when soils are not frozen, wetter active layers in summer, and greater ice content in the upper soil layer during winter. To the extent that the increase in precipitation occurs as an increase in snowfall during the cold season, snow depth and snow water equivalent will increase, although the seasonal duration of snow cover may be shorter if, as projected, warming accompanies the increased snowfall.

The projected changes in terrestrial watersheds will increase moisture availability in the upper soil layers in some areas, favoring plant growth in areas that are presently moisture-limited. The projected increase in river discharge during winter and spring is likely to result in enhanced fluxes of nutrients and sediments to the Arctic Ocean, with corresponding impacts on coastal marine ecosystems. Higher rates of river and stream flow are likely to have especially large impacts on riparian regions and flood plains in the Arctic. One important consequence is that the vast wetland and bog ecosystems of this region are very likely to expand, leading to higher CH4 emissions.

Impacts on the economy (18.3.2.3)

A potentially major impact on the economy of Region 2 and on the global economy could be the opening of the Northern Sea Route (Northeast Passage) to commercial shipping. Model projections of ice cover during the 21st century show considerable development of ice-free areas around the entire Arctic Basin. Most coastal waters of the Eurasian Arctic are projected to become relatively ice free during September by 2020, with more extensive melting occurring later in the century. Ships navigating the Northern Sea Route would clearly benefit from these ice-free conditions. In addition, if winter multi-year sea ice in the central Arctic Ocean continues to retreat, it is very likely that first-year sea ice will dominate the entire maritime Eurasian Arctic, with a decreasing frequency of multi-year ice intrusions into the coastal seas and more open water during the summer. By 2100, one of the ACIA-designated models projects that the navigation season could be as long as 200 days, while the mean of the five ACIA-designated models projects a navigation-season length of 120 days (when defined as the period with seaice concentrations below 50%).

Such changes in sea-ice conditions are likely to have important implications for ship design and construction and route selection along the Northern Sea Route in summer and even in winter. The need for navigational aids, refueling and ship maintenance, and sea-ice monitoring will require major financial investment, however, to assure security and safety for shipping and protection of the marine environment.

The coal and mineral extraction industries in Region 2 are important parts of the Russian economy, but climate change is likely to have little effect on the actual extraction process. On the other hand, transportation of coal and minerals will be affected in both a positive and negative sense. Mines in Siberia that export their products by ship will experience savings resulting from reduced sea-ice extent and a longer shipping season. However, mining facilities relying on transport over roads on permafrost will experience higher maintenance costs as the permafrost thaws.

Forestry, another important sector of the Siberian economy, is likely to experience both positive and negative impacts.A potentially longer growing season and warmer climate are likely to enhance productivity. However, more frequent fires and insect outbreaks are likely as the climate warms and insects invade from warmer regions. Drying of soils as permafrost thaws is also likely to affect forest productivity in some areas. To meet the demands of the global economy, forestry is likely to become more important and transportation of wood and wood products to markets will improve as reduced sea-ice extent facilitates marine transport along the Siberian coast.

Impacts on people’s lives (18.3.2.4)

The change to a wetter climate is likely to lead to increased water resources for the region’s residents. In permafrost-free areas, water tables are very likely to be closer to the surface, and more moisture is projected to be available for agricultural production. During the spring when enhanced precipitation and runoff are very likely to cause higher river levels, the risk of flooding will increase. Summer soil moisture changes remain an open question since the models do not give clear signals. It is possible that lower water levels will occur in summer, as projected for other regions (for example the Mackenzie River in Region 3), affecting river navigation in some areas, increasing the risk of forest fires, and affecting hydropower generation.

Other major environmental impacts projected for Region 2 are associated with thawing permafrost and melting sea ice.Warming during the 20th century produced noticeable impacts on permafrost, causing deeper seasonal thawing and changes in the distribution and temperature of the frozen ground. For example, from the late 1980s to 1998, temperatures in the upper permafrost layers increased by 0.1 to 1.0 ºC on the western Yamal Peninsula. Permafrost degradation in the developed regions of northeast Russia, coupled with inadequate building design, has led to serious problems. For example, in 1966 a building affected by thermokarst and differential thaw settlement collapsed in Norilsk, killing 20 people. In Yakutsk, a city built over permafrost in central Siberia, more than 300 structures, including several large residential buildings, a local power station, and a runway at the airport, have been seriously damaged by thaw-induced settlement. Considerable advances in knowledge and technology for building on permafrost have been made in recent decades.

Nevertheless, as global climate change continues to intensify changes in arctic climate, detrimental impacts on infrastructure and therefore on the economy, health, and well-being of the population throughout the permafrost regions are expected to increase.

Region 3 (18.3.3)

Changes in climate (18.3.3.1)

Alaska experienced an increase in mean annual temperature of about 2 to 3 ºC between 1954 and 2003. The temperature increase was similar in the western Canadian Arctic, but was only about 0.5 ºC in the Bering Sea and Chukotka.Winter temperatures over the same period increased by up to 3 to 4 ºC in Alaska and the western Canadian Arctic, but Chukotka experienced winter cooling of between 1 and 2 ºC (see Fig. 18.2 for regional details).

The five ACIA-designated models project that mean annual temperatures will increase by 3 to 4 ºC by the late 21st century (see Fig. 18.5 for regional details). All the models project that the warming is likely to be greater in the north, reaching up to 7 ºC in winter. In the central Arctic Ocean, winter temperatures are projected to increase by up to 9 ºC as a result of reduced sea-ice extent and thickness, but there is likely to be very little change in summer temperature. Trends in and future projections of ozone and UV radiation levels follow the Arctic-wide patterns.

Impacts on the environment (18.3.3.2)

Two detailed assessments of the potential consequences of climate variability and change have been conducted in Region 3: one for the Mackenzie River watershed in Canada^[9] and the other for Alaska and the Bering Sea as part of the US Global Change Research Program. The Canada Country Study described impacts in the Yukon Territory. These assessments provided background information and input for this assessment. No detailed impact studies have been conducted for Chukotka.

The entire region, but particularly Alaska and the western Canadian Arctic, has undergone a marked change over the last three decades, including a sharp reduction in snow-cover extent and duration, shorter river- and lakeice seasons, melting of mountain glaciers, sea-ice retreat and thinning, permafrost retreat, and increased active layer depth. These changes have caused major ecological and socio-economic impacts, which are likely to continue or worsen under projected future climate change.

Thawing permafrost and northward movement of the permafrost boundary are likely to increase slope instabilities, which will lead to costly road replacement and increased maintenance costs for pipelines and other infrastructure. The projected shift in climate is likely to convert some forested areas into bogs when ice-rich permafrost thaws. Other areas of Alaska, such as the North Slope, are expected to continue drying. Reduced sea-ice extent and thickness, rising sea level, and increases in the length of the open-water season in the region will increase the frequency and intensity of storm surges and wave development, which in turn will increase coastal erosion and flooding.

Warmer temperatures have resulted in some northward expansion of boreal forest, as well as significant increases in fire frequency and intensity, unprecedented insect outbreaks, and a 20% increase in growing-degree days. The latter has benefited both agriculture and forestry. The expansion of forests in most areas and their increased vulnerability to fire and pest disruption are projected to increase. One simulation projects a three-fold increase in the total area burned per decade, destroying coniferous forests and eventually leading to a deciduous forest-dominated landscape on the Seward Peninsula in Alaska, after a warmer climate has led to forestation of the present tundra areas. Shrubbiness is already increasing in this area, a trend that is likely to continue.

Observations in the Bering Sea have shown abnormal conditions during recent years. The changes observed include significant reductions of seabird and marine mammal populations, unusual algal blooms, abnormally warm water temperatures, and low harvests of salmon on their return to spawning areas. Some of the changes observed in the 1997 and 1998 summers, such as warmer ocean temperatures and altered currents and atmospheric conditions, may have been exacerbated by the very strong El Niño event, but the area has been undergoing change for several decades. While the Bering Sea fishery has become one of the world’s largest, the abundance of Steller sea lions (Eumetopias jubatus) has declined by between 50 and 80%. Northern fur seal (Callorhinus ursinus) pups on the Pribilof Islands – the major Bering Sea breeding grounds – declined by 50% between the 1950s and the 1980s. There have been significant declines in the populations of some seabird species, including common murre (Uria aalge), thickbilled murre (U. lomvia), and red- and blacklegged kitti wakes (Rissa brevirostris and R. tridactyla, respectively). Also, the number of salmon has been far below expected levels, the fish were smaller than average, and their traditional migratory patterns seemed to have altered.

Differentiating between the various factors affecting the Bering Sea ecosystem is a major focus of current and projected research.Well-documented climatic regime shifts occurred in the Bering Sea during the 20th century on roughly decadal time scales, alternating between warm and cool periods. A climatic regime shift occurred in the Bering Sea in 1976, changing the marine environment from a cool to a warm state. Information from the contrast between the warm and subsequent cool period forms the basis of projected responses of the Bering Sea ecosystem to scenarios of future warming. These projections show increased primary and secondary productivity with greater carrying capacity, poleward shifts in the distribution of some cold-water species, and possible negative effects in ice-associated species.

Impacts on the economy (18.3.3.3)

Large oil and gas reserves exist in Alaska along the Beaufort Sea coast and in the Mackenzie River/Beaufort Sea area of Canada. To date, climate change impacts on oil and gas development in Region 3 have been minor but are likely to result in both financial costs and benefits in future. For example, offshore oil exploration and production is likely to benefit from less extensive and thinner sea ice, allowing savings in the construction of platforms that must withstand ice forces. Conversely, ice roads, now used widely for access to offshore activities and facilities, are likely to be less safe and usable for shorter periods; the same applies for over-snow transport on land given projected reductions in snow depth and duration. The thawing of permafrost, on which buildings, pipelines, airfields, and coastal installations supporting oil development are located, is very likely to adversely affect these structures and greatly increase the cost of maintaining or replacing them.

It is difficult to project impacts on the lucrative Bering Sea fisheries because many factors other than climate are involved, including fisheries policies, market demands and prices, harvesting practices, and fisheries technology. Large northward changes in the distribution of fish and shellfish are likely with a warmer climate. Relocating the fisheries infrastructure (fishing vessels, home ports, processing plants) may be necessary, and would incur substantial costs.Warmer waters are likely to lead to increased primary production in some regions, but a decline in cold-water species such as salmon and pollock.

Other economic sectors in this region, including forestry and agriculture, are far less developed and currently less important than oil and gas and fish and wildlife. Owing to this, economic impacts on forestry and agriculture resulting from climate change are unlikely to be significant, except locally. Impacts on tourism, which is a large economic sector in this and other regions, are more difficult to assess, largely due to the relationship between tourism and economic conditions and social factors outside the Arctic. It is also unclear which features of Region 3 are primarily responsible for attracting tourists – large, undeveloped landscapes will not be directly affected by climate change, whereas marine mammal populations and accessible glaciers are likely to experience major changes.Whether such changes will reduce tourist interest is difficult to assess without more information.

Impacts on people’s lives (18.3.3.4)

Traditional lifestyles are already being threatened by multiple climate-related factors, including reduced or displaced populations of marine mammals, seabirds, and other wildlife, and reductions in the extent and thickness of sea ice, making hunting more difficult and dangerous. Indigenous communities depend on fish, marine mammals, and other wildlife, through hunting, trapping, fishing, and caribou/reindeer herding. These activities play social and cultural roles that may be far greater than their contribution to monetary incomes. Also, these foods from the land and sea make significant contributions to the daily diet and nutritional status of many indigenous populations and represent important opportunities for physical activity among populations that are increasingly sedentary.

Climate change is likely to have significant impacts on the availability of key marine and terrestrial species as food resources. At a minimum, salmon, herring, char, cod, walrus, seals, whales, caribou, moose, and various species of seabird are likely to undergo shifts in range and abundance. This will entail major local adjustments in harvest strategies and allocations of labor and equipment.

The following impacts on the lifestyles in indigenous villages and communities in Alaska and Canada, which depend heavily on fishing and hunting, have been observed in recent years:

• access to tundra and offshore food resources has been impeded by higher temperatures with milder winters, shorter duration of snow cover and sea ice, and less (or no) shore-fast ice and snow;
• recent decreases in anadromous fish stocks, which make up 60% of wildlife resources harvested by local residents, have directly affected their dietary and economic well-being;
• availability of marine mammals for local harvests has declined in some areas due to population declines associated with shifts in oceanographic and sea-ice conditions. Marine mammals are an important food source in many coastal communities;
• sea-level rise, permafrost thawing, and storm surges have triggered increased coastal erosion and threatened several villages along the Bering and Beaufort Sea coasts. The only long-term option available has been to plan for relocation of villages, which will be very costly;
• storm surges have also reduced the protection of coastal habitats provided by barrier islands and spits, which are highly vulnerable to erosion and wave destruction; and
• infrastructure in villages constructed in or over permafrost has been affected by thawing permafrost and storm surges breaching coastlines into water supplies and sewage lagoons.

Changes in diet, nutritional health, and exposure to air-, water-, and food-borne contaminants are also likely. Adjustments in the balance between the “two economies” of rural areas (traditional and wage) will be accelerated by climate change. This suite of changes will be complex and largely indirect because of the mediating influences of market trends, the regulatory environment, and the pace and direction of rural development. Other impacts are likely to occur in the future and have a substantial impact on people. For example:

• a decrease in the area of pack ice is projected to have important implications for primary productivity and the entire food chain. For example, walrus (Odobenus rosmarus) and bearded seals (Erignathus barbatus) require sea ice strong enough to support their weight, and ringed seals require stable shore-fast ice with adequate snow cover. Diving from ice over shallow waters allows walrus to reach the bottom to feed, and reductions in the extent and thickness of sea ice will adversely affect this species;
• as the boreal forest and associated shrub communities expand northward at the expense of tundra, changes in habitats, migration routes, ranges, and distribution and density of a number of wildlife species, particularly caribou and moose, are projected;
• a change in vegetation and landscape, affecting wildlife, is likely to change hunting practices, location of settlements, and local economic opportunities for people in many arctic regions;
• among wildlife species used as food, existing zoonotic diseases such as brucellosis and echinoccus are likely to become a greater threat to humans and wildlife. New diseases, such as West Nile virus, are likely to become established in a progressively warmer climate;
• lower water levels in some river basins, for example the Mackenzie River, cause increased erosion of riverbanks due to thawing permafrost. This erosion is very likely to increase the incidence of landslides, which have the potential to adversely affect community infrastructure; and
• more vigorous atmospheric and oceanic circulations are likely to increase the transport of contaminants from agricultural activities as well as military and industrial installations to arctic communities, both directly and via the food chain.

Region 4 (18.3.4)

A major integrative impact assessment for the region was published by Maxwell for the Canadian Arctic (encompassing the regions of the Northwest Territories and Nunavut). The Mackenzie River watershed assessment, mentioned in the summary for Region 3, also covers Region 4. A number of studies of the traditional ecological knowledge of indigenous peoples of Region 4 have been conducted and are cited in earlier chapters. Detailed studies of integrated climate impacts in Greenland, on the other hand, have not been conducted prior to the ACIA.

Changes in climate (18.3.4.1)

Temperature changes over the past decades have varied across Region 4. The amount of change depends on the time period chosen and, as shown in Chapter 2, the warming has been pronounced since 1966. Between 1954 and 2003, mean annual temperatures across most of arctic Canada increased by as much as 2 to 3 ºC (see Fig. 18.2a), while temperatures in northeastern Canada, including Labrador and adjacent waters, showed little change. The southern part of West Greenland (including the surrounding ocean) cooled by about 1 ºC while northern Greenland warmed by 1 to 2 ºC.Winter temperature trends over the same period were noticeably warmer in the west and colder in the east than the annual trends (Fig. 18.2b). The landmass to the west of Hudson Bay warmed by up to 4 ºC in winter while the area around Labrador, Baffin Island, and southwest Greenland experienced winter cooling of more than 1 ºC.

Annual precipitation in Region 4 has increased over the past 50 years or so, and while seasonal differences were evident around the middle of the century, increases in precipitation have been evident in all seasons over the past few decades.

The physical complexity of the Queen Elizabeth Islands and the orography of Greenland create particular challenges for modeling past, present, and future arctic climate. Models project warming throughout Region 4 during the 21st century, with no cooling projected in any season. Figures 18.5a and 18.5b illustrate annual and winter temperature changes for the period 2071–2090 relative to the 1981–2000 baseline, projected by the five ACIA-designated models forced with the B2 emissions scenario. Projected winter warming in the Canadian areas of Region 4 ranges from about 3 ºC up to about 9 ºC, with the greatest warming projected to occur around southern Baffin Island and Hudson Bay, and substantially less warming projected in other seasons. Greenland is also projected to warm but the warming is weaker (up to about 3 ºC by 2071–2090) and more consistent across seasons.

Precipitation increases are projected to be greatest in autumn and winter, and the areas of greatest increase (up to 30% by the end of the 21st century) generally 1012 Arctic Climate Impact Assessment correspond with the areas of greatest warming. Almost all areas of Region 4 are projected to experience some increase in precipitation after the first few decades of the 21st century.

Impacts on the environment (18.3.4.2)

The Canadian part of Region 4 has significant areas of warm permafrost that are at risk of thawing with rising regional air temperatures. The boundary between continuous and discontinuous permafrost is projected to shift poleward, following, but with a lag in timing, the several-hundred-kilometer movement of the isotherms of mean annual temperature over the 21st century.

This is likely to result in the disappearance of a substantial amount of the permafrost in the present discontinuous zone. Areas of warm permafrost are also likely to experience more widespread thermokarst development where soils are ice-rich, and increases in slope instability. In areas of remaining continuous and cold permafrost, increases in active-layer depth can be expected. The maximum northward retreat of sea ice during summer is projected to increase from its present range of 150–200 km to 500–800 km. The thickness of fast ice in the Northwest Passage is likely to decrease substantially from its current value of 1 to 2 m.

The Greenland Ice Sheet is presently losing mass in its ablation zone and is likely to contribute substantially to sea-level rise in the future.While precipitation is projected to increase, it is possible that increased evaporation rates will lead to lower river and lake levels during the warm season.

In general terms, and consistent with results for other regions, the biomes of arctic Canada and Greenland are expected to change. Reductions in the area covered by polar deserts in Canada and Greenland are likely to result from the northward shift of the tundra, while reductions in the areas covered by arctic tundra are very likely to result from the northward shift of the treeline. Polar deserts in the region are extensive, and these areas could sequester large amounts of carbon dioxide (CO2) if tundra vegetation displaces polar deserts. A reduction in polar desert area of about 36% by 2080 is projected, leading to the greatest projected carbon gain of any region. In contrast, increases in temperature and precipitation are likely to lead to relatively small increases in the area of taiga compared with other regions.

Many treelines, such as those in northeast Canada, have been relatively stable for the last few thousand years. A widespread and consistent observation from the late 20th century has been the infilling of sparse stands of trees near the tundra edge into dense stands that no longer retain the features of the tundra. Movement of the treeline northward is likely when climatic conditions become favorable, but the actual movement of trees will lag the climate warming considerably in time. The forests of northwestern Canada have recently experienced forest health problems driven by insects, fire, and tree growth stress that are all associated with recent mild winters and warmer growing seasons. These findings for Region 4 complement those of Region 3 and accord with very large-scale environmental changes in the western North America subarctic. It is very likely that such forest health problems will become increasingly intense and widespread in response to future regional warming.

The Canadian High Arctic is characterized by land fragmentation within the archipelago and by large glaciated areas, leading to constraints on species movement and establishment. In West Greenland, loss of habitat and displacement of species in combination with time delays in species immigration from the south will ultimately lead to loss of the present biodiversity. However, Region 4 contains relatively few rare and endemic vascular plant species and threatened animal and plant species, compared with the other three regions, so biodiversity losses are likely to be less significant here.

Changes in timing and abundance of forage availability, insect harassment, and parasite infestations will increase stress on caribou, tending to reduce their populations. The ability of high-arctic Peary caribou and muskoxen to forage may become increasingly limited as a result of adverse snow conditions, in which case numbers will decline, with local extirpation in some areas. Direct involvement of the users of wildlife in its management at the local level has the potential for rapid management response to changes in wildlife populations and their availability for harvest.

Arctic freshwater systems are particularly sensitive to climate change because many hydro-ecological processes respond to even small changes in climatic regimes. These processes may change in a gradual way in response to changes in climate or in an abrupt manner as environmental or ecosystem thresholds are exceeded. Pronounced potential warming of freshwater systems in the autumn is particularly important because this is typically when these systems along the coastal margins currently experience freeze-up. Such warming is projected to delay freeze-up by up to 25 days in parts of Region 4. Also, high-latitude cold-season warming is likely to lead to less severe ice breakups and flooding as the spring flood wave pushes northward along arctic rivers. Hence, future changes in the spring timing of lake- and river-ice breakup and the export of freshwater to the Arctic Ocean are likely.

With respect to freshwater ecosystems, significant shifts in species range, composition, and trophic relations are also very likely to occur in response to the projected changes. Salmonids of northern Québec and Labrador, such as native Atlantic salmon and brook trout (Salvelinus fontinalis) and introduced brown trout (Salmo trutta) and rainbow trout (Oncorhynchus mykiss), are likely to extend their ranges northward. Because of these range extensions, the abundance of Arctic char (Salvelinus alpinus) is likely to be reduced throughout much of the southern part of Region 4, and brook trout are likely to become a more important component of native subsistence fisheries in rivers now lying within the tundra zone. Lake trout (Salvelinus namaycush) are also likely to disappear from rivers and the shallow margins of many northern lakes, and northern pike (Esox lucius) are expected to reduce in both numbers and size throughout much of their current range.

Marine mammal populations are likely to decline as the sea ice recedes but the populations of beluga and bowhead whales (Delphinapterus leucas and Balaena mysticetus, respectively) could increase (depending on the extent to which these whales become more vulnerable to predation as sea-ice cover decreases). If the Arctic Ocean becomes seasonally ice free for several years in a row, it is possible that polar bears would become extinct. Sea-level rise will change the location and distribution of coastal habitats for seabirds and some species of marine mammals (e.g., walrus haul-outs may become inundated).

Impacts on the economy (18.3.4.3)

Oil and gas extraction and mining are active industries in Region 4. Diamond mining is underway in the Northwest Territories, and the development of a large nickel deposit in Voisey’s Bay, Labrador, has recently been announced. Many rivers in the northern parts of Québec, Ontario, and Manitoba have been dammed for their hydroelectric potential. Roads, airstrips, and ports have been constructed and are essential to the economic infrastructure supporting these activities. Any expansion of oil and gas activities, mining, agriculture, or forestry is likely to require expansion of supporting infrastructure, including air, marine, and land transportation systems. Ice roads in nearshore areas and over-snow transport on land, systems that are important and are even now experiencing shorter seasons, are likely to be further curtailed in the future because of reduced extent and duration of sea ice and snow.

With reduced summer sea-ice extent, the shipping season in Canadian arctic waters is likely to be extended, although sea-ice conditions are likely to remain very challenging. Extension of the shipping season will result in costs and benefits, both of which are speculative. Benefits are likely to result from increased access to the natural resources of the region. As sea level rises, this will also benefit shipping by creating deeper drafts in harbors and channels. On the other hand, increased costs would result from greater wave heights, and possible flooding and erosion threats to coastal facilities. Increased rates of sediment movement during longer, more energetic open-water seasons are likely to increase rates of port and harbor infill and increase dredging costs. Increased ship traffic in the Northwest Passage will increase the risks and potential environmental damage from oil and other chemical spills.

Warmer air temperatures would be expected to reduce the power demand for heating, reduce insulation needs, and increase the length of the summer construction season. Other infrastructure likely to be affected by climate change includes northern pipeline design (negative); pile foundations in permafrost (negative but depending on depth of pile); bridges, pipeline river crossings, dikes, and erosion protection structures (negative); and openpit mine wall stability (negative).

Impacts on marine fisheries in the eastern part of Region 4, under a moderate gradual warming, are likely to include a return to a cod–capelin system with a gradual decline in northern shrimp and snow crabs. Under more modest assumptions of ocean warming, the range of demersal species (those that tend to live near the bottom) are expected to expand northward. If ocean warming is more extreme, it is likely that the southern limit of the range of the demersal species would move northward. Many existing capelin-spawning beaches are likely to disappear as sea levels rise. If there is an increase in demersal spawning by capelin in the absence of new spawning beaches, capelin survival may decline. Seals may experience higher pup mortality as sea ice thins. Increases in regional storm intensities may also result in higher pup mortality. A reduction in the extent and duration of sea ice is likely to permit fishing further to the north and is likely to shorten the duration of Greenland halibut fisheries that are conducted through fast ice.

Impacts on freshwater and anadromous fisheries, and their economic benefits, such as tourism and local economic development, will vary across Region 4 and will depend on the local present-day and future species composition. Initially, local productivity associated with present-day freshwater and anadromous species is likely to increase, but as critical thresholds are reached (e.g., thermal limits) and as new species move in to the area, arctic-adapted species such as Arctic char are likely to experience declines in abundance and ultimately become extirpated. Loss of suitable habitat will result in decreased individual growth and declines of many populations, with resulting impacts on sport fisheries and local tourism.

Impacts on people’s lives (18.3.4.4)

The changes in climatic and environmental conditions projected for Region 4, and already being observed in some parts, affect people’s lives in many ways. Seasonal unpredictability throughout Region 4 has already created dangerous environmental situations. For example, for the Inuit west of Hudson Bay, changing wind patterns and snow conditions make it difficult to build igloos as the snow is packed too hard. As a result, Inuit report increasing difficulty in building shelters during unexpected storms. In areas of Nunavik and Labrador the snow changes can differ, for example the type of snow now seen does not pack well enough. Changes in weather and ice conditions, such as earlier spring melt, later freeze-up, and formation of more cracks, such as those reported in the Kitikmeot region of Nunavut, result in increasingly difficult travel conditions and sometimes shifts in regular travel and harvesting times.

The changes in local environments experienced by the people in the Canadian part of Region 4 include thinner sea ice, early breakup and later freeze-up of sea ice and lake ice, sudden changes in wind direction and intensity, earlier and faster spring melt periods, decreasing water levels in mainland lakes and rivers, and the introduction of non-native animal and bird species. These changes affect lifestyles through changes in the timing of animal migrations as well as in the numbers and health of some animal populations, and in the quality of animal skins and pelts. The distribution and quality of animals and other resources will affect the livelihoods, and ultimately the health of northern communities in Region 4. For example, a shorter winter season with increased snowfall and less extensive and thinner sea ice is likely to decrease the opportunity and increase the risks for indigenous people to hunt and trap.

Other health impacts may arise from the introduction of new or increasingly present zoonotic and/or vectorborne diseases (e.g., potential spread of West Nile virus into warmer regions in the western Arctic), changes in exposure to UV radiation and contaminants that already threaten confidence in and safety of traditional diets, and the associated social and cultural impacts of this combination of changes. Relocation of low-lying communities may be forced by rising sea levels, with serious social impacts.Where these challenges to health already exist, and where infrastructure and support systems are stretched, the effects are likely be experienced to a greater extent and at a faster pace than elsewhere.

Many changes are reported and are currently experienced by Inuit, Dene, Gwitch’in, and other indigenous peoples in Region 4. These changes represent challenges to aspects of northern indigenous cultures and lifestyles that have existed for centuries. The ability of communities to cope with and adapt to climate-driven changes is also influenced by a number of other factors and is constrained by current social and economic aspects. For example, moving people to follow shifting resources is no longer an option with permanent settlements. Other factors complicating adaptations to change include regional resource regulations, industrial development, and global economic pressures. Climate change interacts with such forces and must be considered in assessing local risks and responses. As existing adaptation strategies become obsolete, new adaptations to climate impacts must develop as northern communities adjust to the many social, institutional, and economic changes related to land claim settlements, changes in job opportunities, and the creation of new political and social structures in the North.

Chapter 18: Summary and Synthesis of the ACIA
18.1. Introduction
18.2. A summary of ACIA conclusions
18.3. A synthesis of projected impacts in the four regions
18.4. Cross-cutting issues in the Arctic
18.5. Improving future assessments
18.6. Conclusions (Projected climate change impacts in the four regions of the Arctic)

References

NOTE:This chapter is a summary based on the seventeen preceding chapters of the Arctic Climate Impact Assessment and a full list of references is provided in those chapters. Only references to major publications and data sources, including integrative regional assessments, and some papers reporting the most recent developments, are listed.

1. {{note|9}Cohen, S.J. (ed.), 1997a. Mackenzie Basin Impact Study (MBIS) Final Report. Environment Canada, 372p.-- Cohen, S.J., 1997b.What if and so what in Northwest Canada: could climate change make a difference to the future of the Mackenzie Basin. Arctic, 50:293–307.

Citation

Committee, I. (2012). Projected climate change impacts in the four regions of the Arctic. Retrieved from http://editors.eol.org/eoearth/wiki/Projected_climate_change_impacts_in_the_four_regions_of_the_Arctic