The Threat of Climate Change to Arctic Wildlife

May 1998

"Arctic ecosystems exist in a delicate balance with the region's climate and, based on their reaction to different climates in the past, are likely to change significantly under future climate change."

-- F. Stuart Chapin, et al, Arctic Ecosystems in a Changing Climate: an Ecophysiological Perspective, Academic Press, Inc., San Diego, 1992.

The Arctic is home to some of the world's most distinctive mammals, millions of migratory and resident birds, a rich ice-edge community, and some of the world's major fisheries. The area is a biologically and culturally unique environment and one of the last places on Earth where natural conditions still prevail over much of the region.[1]

The Arctic also plays a major role in regulating global climate. Air and water interactions in the region influence ocean circulation patterns; the reflectivity, or albedo, of polar snow and ice limits the amount of sunlight and heat absorbed by the Earth; and layers of peat and permafrost store vast amounts of carbon.

The Arctic, however, faces drastic change. The global build-up of greenhouse gases has the potential to dramatically alter the Arctic environment and its ecosystems. [2] The Arctic is particularly vulnerable to climate change, and indeed in some areas the impacts of changes in climate are already evident. Future climate change is likely to threaten both marine and terrestrial wildlife. From plankton to polar bears, many species could suffer or disappear entirely.

The Arctic's response to climate change concerns us all, for the region serves as an important indicator for what may occur in other regions, and around the globe.

Human Influence on Climate

In December, 1995, the United Nations-affiliated Intergovernmental Panel on Climate Change (IPCC) issued its landmark finding that human activities have begun to significantly modify global climate. In the IPCC's words, "the balance of evidence suggests a discernible human influence on global climate." Even under the best-case scenarios, the rate of future warming will probably be greater than any seen in the last 10,000 years. [3]

A variety of human activities produce greenhouse gases, like carbon dioxide (CO2), nitrous oxide (N20), and hydrofluorocarbons (CFCs, HCFCs, and HFCs), methane (CH4), and sulfur hexafluoride (SF6), increasing their atmospheric concentrations. These industrial emissions trap the sun's heat and warm the planet. In the U.S., fossil fuel combustion is the most significant cause of greenhouse gas emissions, and has contributed to dramatic increases in CO2 levels.

Since pre-industrial times, atmospheric CO2 concentrations have gone up 30 percent, from 280 parts per million to more than 360 parts per million; in the last 35 years alone, CO2 levels increased over 12 percent. If this trend continues, CO2 concentrations will double by the end of the next century. Humans will continue to drive future climate change, with potentially catastrophic and irreversible consequences, if action is not taken now to reduce greenhouse gases.[4]

Vulnerable to Change

Scientists have long predicted that human-induced climate change will have its first and most severe impacts in the polar regions. The Arctic's unique physical characteristics help explain why the region is so vulnerable. Encompassing much of Alaska, northern Canada, Greenland, northern Scandinavia, Siberia, and the vast Arctic Ocean, the Arctic has one of the most severe environments on the planet. Temperatures are extremely low, sunlight and precipitation are limited, and the growing season is short, averaging only 50 to 100 days. Arctic sea ice, snow cover, tundra and permafrost are highly susceptible to even subtle variations in sunlight, surface temperature, and precipitation. Ecosystems in the Arctic exist in delicate balance with the region's climate, and so are more sensitive to change than temperate or tropical ecosystems.[5]

Despite this harsh environment, the Arctic supports amazing marine and terrestrial wildlife. Many of the world's most distinctive mammals -- including walruses, several species of seals, caribou, reindeer, collared lemmings, Arctic foxes, muskoxen, narwhals, bowhead and beluga whales and polar bears -- live only in the Arctic. The Arctic is also a haven for migratory birds, where an estimated 15 percent of all the world's species spend their breeding season. The southern boundaries of the Arctic also support some of the world's major ocean fisheries.

Change is Underway

Evidence suggests that climate changes are already impacting natural environments in the Arctic. Large fluctuations in wildlife populations, thinning sea ice over once-stable areas, rising lake temperatures, thawing permafrost and regional warming are a few of the recent signs of change.[6] Annual temperatures have increased by about 2.7 degrees F -- many times the global rate -- over parts of Canada's western Arctic, Alaska, and eastern Siberia. The most pronounced warming has occurred during winter and spring, in areas such as Canada's Mackenzie River Basin, the Bering Straits, and Siberia's Lake Baikal.

Inuit communities--whose knowledge of the land, sea, and ice dates back thousands of years -- have documented these signs of change throughout the region. [7] The Gwich'in people of Arctic Village, Alaska have observed marked changes in weather, hydrology, vegetation, and animal distribution patterns, indicating that warming trends have occurred during the lifetimes of community residents. Scientific observations appear to confirm these Alaska Native accounts.[8]

Effects of Future Climate Change

The effects of climate change are likely to be severe and irreparable: A doubling of atmospheric carbon dioxide (CO2) may result in Arctic winters more than twice as warm as the current average, with winter temperatures increasing between 12 and 6 degrees F through much of the region. [9] Sea ice is likely to disappear in many areas, especially during summer, while thinning in winter. According to scientific projections, ice would retreat from much of the southern half of Hudson Bay, the northern Labrador and southern Greenland seas, the entire Bering Sea, and a broad band of the Barents Sea, above Scandinavia. The snow season could shorten by a month or more, reducing snow cover by 40 or even 70 percent. Large areas of permafrost in Canada and Siberia could disappear entirely, and some permafrost boundaries, as in Western Canada, would shift northward. Periods of unusually inclement weather could become more frequent. And melting land ice -- combined with thermal expansion of ocean waters -- could cause a global sea level rise of up to three feet. [10] The physical and biological impacts of all this change on Arctic ecosystems could be tremendous.[11]

Threatened Wildlife

Marine Life

The biological importance of the Arctic marine environment is often underestimated. The cold waters, ice, and ice edges of the Arctic seas are enormously productive, where seasonal phytoplankton and algae blooms support the entire Arctic food web. [12] Arctic species are dependant upon and adapted to floating sea ice and ice edges.

Although a few degrees' increase in seawater temperature may not seem critical, the consequences would affect the Arctic marine ecosystem in many ways. Warmer temperatures may increase biological productivity in some parts of the marine ecosystem. Reductions in sea ice extent and algae could, in turn, lead to profound reductions in overall biological productivity in the Arctic seas. The entire ice-associated community could be threatened, including its dependent fish species, such as polar cod. Arctic and migratory whale species, such as the narwhal and beluga whales, gray and bowhead whales, would be affected, since they feed along the ice edge. Large populations of Arctic marine birds would also be threatened. Birds and mammals may be affected by climate-induced changes in ice openings called leads and polynyas, which serve as critical "outposts" for feeding, breeding and migration. [13]

Animals that depend on the ice as a platform, such as ringed seals, walruses and polar bears, would be left vulnerable by the loss of their habitat. [14] Walrus may suffer first, since they are dependent over much of their range on seasonal sea ice. Polar bears could also become extinct if the Arctic Ocean is free of summer ice for long periods, or if seasonal sea ice changes affect ringed seals, their main prey. Regional variations in distribution and abundance of sea ice already have had significant effects on the reproduction and survival of polar bear populations.

If further warming occurs, ice is likely to break-up earlier and freeze later, extending the open-water season in summer and fall. This change could result in more effort required by the bears to hunt for the same amount of food and could reduce reproductive rates. [15]

Persistent organic pollutants already pose an imminent threat to polar bears. These pollutants, including PCBs and DDT, tend to condense, deposit, and accumulate in cold ecosystems; polar seas may have higher concentrations than other marine environments. The pollutants have toxic effects on animal reproduction, development, and immunological function. [16] Scientists have documented declining polar bear birth rates and physical conditions in Canada's western Hudson Bay. This decline could be an indication that the bear population is weakening from bio-accumulated persistent organic pollutants. Warmer temperatures could, potentially, accelerate the pollution's rate of migration, and intensify the impacts on polar bears and other animals. Interestingly, scientists consider the polar bear as the ideal "indicator" species of climatic warming and ecological change in the Arctic, given the bears' position atop the Arctic marine food chain. [17]

Finally, major North Atlantic fisheries, which already have been severely over-fished by factory trawlers, may suffer continued decline, as further changes in ocean currents and circulation patterns cool off waters in the region. [18] Ironically, temperatures are now cooler in some areas (Labrador Sea, western Greenland, eastern Baffin Island), a trend that is consistent with predictions of climate change impacts. Some commercial fish populations have collapsed in the region, as waters have become generally colder and over-fishing has worsened.[19]

Terrestrial Life

On land, wildlife will face similar threats. Like ice in the marine environment, vegetation is the land's life-sustaining feature. Scientists project that human induced climate changes are likely be more pronounced and rapid than anything Arctic vegetation has ever experienced.[20] Rapid temperature increases in the Arctic are expected to push climate and vegetation zones northward at an astounding distance of 93 - 341 miles over 100 years. Many plant and animal species are unlikely to have time either to adapt to this warming, or to adjust their ranges to keep pace with the shift in climatic zones. [21] Such dramatic shifts in vegetation could jeopardize many animal populations, since abundant vegetation, at the right time, is critically important to all terrestrial wildlife. Grazing animals such as reindeer, caribou and muskox closely track seasonal vegetation growth, and depend upon the vegetation for healthy herds and well-nourished calves. This "plant-herbivore" interaction, as scientists sometimes call it, is an important part of tundra life. Without adequate vegetation, the animals become less productive, delay having offspring, and -- in many cases -- starve.

In the Arctic National Wildlife Refuge, for example, spring has arrived earlier and earlier along the coast. Consequently, caribou have had difficulty migrating from wintering areas in time to take advantage of periods of maximum springtime plant growth. The spring of 1990 was the earliest in nearly 40 years, and by the time the animals reached the plain, their principle food plant had gone to seed. Caribou herd populations could decline significantly, should future climate and vegetation patterns prevent proper nourishment of calves. [22] High Arctic Peary Caribou and muskoxen may even become extinct. [23]

Climate change could also affect regular freeze-thaw cycles, which have important implications for reindeer populations in relation to their ability to find food. In the winter of 1996/97 an estimated 10,000 reindeer died of starvation on Russia's far northeast Chukotka peninsula, after inclement weather patterns formed a thick ice crust over pastures, making it impossible for reindeer to graze. [24] While reindeer populations often suffer from these freeze-thaw cycles, future variations in weather and climate could intensify the cycles' effects.[25]

Climate change is also expected to bring more frequent and extreme weather events, as well, including droughts, floods and severe storms.

The adverse effects of weather patterns on any one animal population could be substantial. [26] Yet another potential risk to polar bears is the increased chance that rain in the late winter will cause polar bear dens to collapse before females and cubs have departed. Scientists surveying polar bear habitat in Manitoba, Canada have observed large snow banks used for denning which had collapsed under the weight of wet snow. [27]

In addition to providing shelter, snow also supports life on land: the health of many plant and animal communities largely depends on the persistence, thickness and timing of snow cover. Normally abundant during most of the year, snow is also very sensitive to changes in climate. While scientific predictions differ over whether snowfall will actually increase or decrease under climate change, a significant increase or decrease in snowfall would upset the present delicate balance.

A Vulnerable Ecosystem

Many biologists doubt that Arctic animals will be able to adapt to climate change. Arctic ecosystems are already considered "stressed," or inherently vulnerable, compared with temperate and tropical ecosystems. This vulnerability is largely due to violent Arctic weather, which can destroy entire animal populations or generations of young birds. It is also due to the short and very sensitive nature of the Arctic food chain. Research suggests that -- unlike their temperate-zoned counterparts -- Arctic animals find it difficult to tolerate the inherent stresses they are accustomed to, as well as new stresses of man-made origin. They are probably more vulnerable to man-made intrusions -- such as climate change -- than the populations of any other animals. There are geographic limitations, as well: the tundra is also the only major environment whose range is completely unable to shift northward in response to warming.

Conclusion

The implications of warming on the Arctic are complex and not yet fully understood. Yet they extend well beyond the immediate region, and may have dramatic global repercussions. Arctic warming may, in fact, accelerate global warming and its effects. Potentially drastic changes in the Arctic serve as a wake-up call to governments and individuals alike to take action now. Greenpeace fully supports deep reductions in greenhouse gas emissions, and a shift away from a fossil fuel-based economy to one based on clean, renewable energy sources. These alternatives have the potential to meet the world's energy needs, create jobs, encourage world trade in clean technologies, and reduce energy costs while protecting the planet. The barriers to these solutions are not technical, but political.

ENDNOTES

[1] Adam Markham, Nigel Dudley and Sue Stolton, Climate Change, Biodiversity and the Survival of Species, World Wildlife Fund publication, Gland, Switzerland, 1993, pp. 68.

[2] Arctic Research Consortium of the United States (ARCUS), People and the Arctic: The Human Dimensions of the Arctic System, Prospectus for Research, University of Alaska, Fairbanks, 1997, p. 1.

[3] Intergovernmental Panel on Climate Change, Working Group I Report, The Science of Climate Change, 1996.

[4] Ibid.

[5] F. Stuart Chapin, et al, Arctic Ecosystems in a Changing Climate: an Ecophysiological Perspective, Academic Press, Inc., San Diego, 1992, p. 31.

[6] The Vulnerability and Role of the Arctic in Global Climate Change, in Oil in Arctic Waters: The Untold Story of Offshore Drilling in Alaska, publication of Greenpeace Alaska Field Office, Anchorage, AK, 1996, p. 111.

[7] Testimony of Rosemarie Kuptana, President, Inuit Circumpolar Conference , before the Second Conference of the Parties to the U.N. Framework Convention on Climate Change, Geneva, Switzerland, July 16-19, 1996.

[8] The Vulnerability and Role of the Arctic in Global Climate Change, op. cit.

[9] Markham, et al, op. cit., p. 65.

[10] F. Stuart Chapin, et al 1992, op. cit., pp. 24-29. See also: IPCC, Working Group II Report, Impacts, Adaptations and Mitigation of Climate Change: Scientific - Technical Analyses, Climate Change Impacts on the Cryosphere (chapter 7), 1996; and Markham, et al 1993,op. cit., pp. 65-67.

[11] Markham, et al 1993, op. cit., p. 67.

[12] Ibid, p. 66.

[13] Vera Alexander, Arctic Marine Ecosystems, in Robert L. Peters and Thomas E. Lovejoy, Global Warming and Biological Diversity, Yale University Press, New Haven, 1992, pp. 221-232.

[14] Ibid, p. 229.

[15] Ian Stirling and Andrew Derocher, Possible Impacts of Climatic Warming on Polar Bears, Arctic, vol. 46, no. 3, September 1993, pp. 240-245.

[16] Frank Wania and Donald Mackay, Tracking the Distribution of Persistent Organic Pollutants, Environmental Science and Technology: News and Research Notes, vol. 30, no. 9, September 1996, pp. 390-395.

[17] Stirling and Derocher 1993, op. cit., p. 244.

[18] The Nordic Arctic Environment: Unspoiled, Exploited, Polluted?, published by the Nordic Council of Ministers, Copenhagen, 1996, p. 217.

[19] ARCUS 1997, op. cit., p. 12.

[20] F. Stuart Chapin, et al 1992, op. cit., p. 446.

[21] Nordic Council of Ministers 1996, op. cit., p. 218.

[22] Jay R. Malcolm, The Demise of an Ecosystem: Arctic Wildlife in a Changing Climate, World Wildlife Fund Report, Washington, D.C., 1996, p. 5.

[23] A. Gunn, Responses of Arctic Ungulates to Climate Change, Human Ecology and Climate Change, Dr. Peterson and Dr. Johnson, Editors. Taylor and Francis, Washington D.C., pp. 90-106.

[24] Jay R. Malcolm, The Demise of an Ecosystem: Arctic Wildlife in a Changing Climate, World Wildlife Fund Report, Washington, D.C., 1996, p. 5.

[25] Nordic Council of Ministers 1996, op. cit., p. 110.

[26] F. Stuart Chapin, et al 1992, op. cit., p. 407.

[27] Stirling and Derocher 1993, op. cit., p. 244.