The climate dictates many aspects of the way of life for all people living in the Arctic. Climate changes are likely to affect the current subsistence economies, habitability, and health of the Arctic people. If warming occurs, there will be striking changes in the landscapes at northern high latitudes. These changes may be exacerbated where they are accompanied by growing numbers of people and increased economic activity (IPCC 1996, WG II, Chapter 7 Executive Summary). There could be a northward spreading of agricultural, forestry, and mining activities-resulting in increased population and intensified settlement patterns-into Arctic areas. The rate of such spread is an issue of debate and will depend on social and economic factors, intervention strategies, and natural processes. Marine, road, rail, and air links would have to be expanded accordingly. Although this development would entail substantial extra capital and operating costs, it also would be an economic opportunity (IPCC 1996, WG II, Section 11.4.4).
Changes in landscape, sea-ice distribution, and river and lake ice could have a major impact on indigenous people who live in Arctic regions and depend upon traditional occupations, food gathering, and hunting. They depend directly on the living resources of the area and often travel on ice, so their livelihood may be widely affected. The resulting redistribution and abundance changes of terrestrial and marine animals that are vital to the subsistence lifestyles of Native communities may have major impacts. Ice roads and crossings commonly are used to link northern settlements. The greatest economic impact is likely to stem from decreases in ice thickness and bearing capacity, which could severely restrict the size and load limit of vehicular traffic (IPCC 1996, WG II, Section 7.5). Road maintenance related to permafrost thawing already is a major problem with high associated costs in many sub-Arctic areas. At the same time, further warming is likely to cause many small settlements, particularly along the coast and on small islands, to be abandoned because of permafrost loss and sea-level rise.
Anticipated hydrological changes and reductions in the areal extent and depth of permafrost could lead to large-scale damage to infrastructure. Some transportation systems, mining activities, and structures will be threatened by thawing (IPCC 1996, WG II, Section 7.5.1). For example, thawing could lead to disruption of existing petroleum production and distribution systems in the tundra unless mitigation techniques are adopted (IPCC 1996, WG II, Chapter 7 Executive Summary). This impact may require changes in the design of oil pipelines to avoid slumping, breaks, and leaks (IPCC 1996, WG II, Section 11.5.4). Fortunately, most of this technology already is in use south of the permafrost line.
Structures such as pipelines, airstrips, community water supply and sewage systems, and building foundations are susceptible to performance problems if existing frozen foundations or subgrades thaw, even minimally. Extensive measures would be needed to ensure the structural stability and durability of installations for tourism, mining, and telecommunication in permafrost areas affected by climate warming. In some cases, existing settlements would become uninhabitable because of permafrost changes. Transport links also could be affected, with serious disruption and increased maintenance costs from ground subsidence, side-slope slumpings, landslides, icings, and ice-mound growth.
On the other hand, many northern cities will spend less money on snow and ice clearance. More frequent periods of open water for rivers, lakes, and seas, however, will produce greater snowfall downwind. This factor will be important near Hudson Bay, the Barents Sea, and the Sea of Okhotsk (IPCC 1996, WG II, 7.4.1). Engineering design criteria will need to be modified to reflect changing snow and frost climates, deepening of the active layer over permafrost, and warming and ultimate disappearance of marginal or discontinuous permafrost. Present permafrost engineering commonly designs for the warmest year in the past 20 years of record; such criteria may need to be reviewed and revised (IPCC 1996, WG II, Section 7.5.1).
Sea-level rise will affect a few outlying Arctic communities, many of which are on the shoreline, as well as major coastal industrial facilities such as the Prudhoe Bay oilfields in Alaska. Sea-level rise also will allow ice-thrust events to be more damaging to the shoreline. Coastal permafrost will be thermally eroded, which will produce local slumping and coastal retreat.
Episodes of extreme cold and blizzards are major climate concerns for circumpolar countries like Russia and Canada (IPCC 1996, WG II, Section 18.104.22.168). However, the Polar regions will remain cold, so the direct effects of global warming are likely to have little effect on human health. Potential indirect effects, such as changes in infectious diseases and vector organisms, are largely unknown. UV-B radiation is increasing, which can damage the genetic (DNA) material of living cells (in an inverse relationship to organism complexity) and induce skin cancers in experimental animals. It also may affect human health: UV-B radiation is implicated in the causation of human skin cancer and lesions of the conjunctiva, cornea, and lens; it also may impair the body's immune system (IPCC 1996, WG II, Section 18.4).
Other reports in this collection