Biodiversity and Global Climate Change

It has become apparent that human industrial activities are affecting the climate on a global scale. Activities such as burning of fossil fuels are releasing huge amounts of so-called greenhouse gases (especially carbon dioxide and methane) into the atmosphere. These greenhouse gases trap the heat that is radiated from the Earth's surface and cause global warming. There is general agreement that the effects of global climate change will be most apparent in Arctic ecosystems. This may include increasing winter temperatures and annual snowfall. The current reduction in the extent and thickness of sea ice can also be attributed to climate warming. These physical effects will have an indirect yet severe impact on the integrity of Arctic ecosystems.

Scientific studies propose, for example, that there will be a strong shift in the habitat ranges of certain animal and plant species. In recent decades, a few mammals with temperate or boreal habitat ranges have already penetrated northward into the Low Arctic, where suitable habitat is available. The moose (Alces alces) and snowshoe hare (Lepus americanus) are examples. Their movement into the Low Arctic may be an indirect consequence of climatic warming. Climate-induced changes could also have far-reaching effects on caribou migration patterns and population dynamics. Caribou rely on sufficient food resources to raise well-nourished calves. Scientists predict that climate change may affect the regular freeze-thaw cycles, resulting in thick ice crusts over winter pastures and, thus, influencing their ability to find food.

Decreases in Arctic sea-ice cover, as a result of increasing temperatures, may also have serious impacts on a number of the region's marine mammal populations. Changes in the extent and concentration of sea ice may influence the seasonal distribution patterns and reproductive success of some species. Seals living on the ice, such as ringed seals, may be particularly vulnerable since they depend on the pack-ice habitat for raising their pups, foraging, molting, and resting. Since the distribution of the polar bear is probably a function of the distribution of ice conditions that allow them to travel and hunt most efficiently, changes in the extent and type of ice cover are expected to affect their distributions and foraging success. In the Hudson Bay area, scientists have found polar bears that exhibit extremely low rates of fat storage during the summer when they are landlocked and unable to hunt. This observation is due to the increasing length of time between the annual breakup and freezeup of the sea ice, which decreases the time available for the polar bears to feed on seals during winter.

Ozone depletion over the North Pole has resulted in increased ultraviolet radiation (UV) flux. The current consensus is that this may cause damage to marine phytoplankton at high latitudes, which will have significant effects on other biological organisms in the food web. Even though the currently observed ozone reduction in the Arctic is smaller than that observed over the Antarctic, some scientists propose that this trend will continue and predict greater ozone losses during the next decade.

In the long run, climate change will act as a selective filter: species that can adapt to warming or shift their population range quickly will survive; other species will decrease and may even become extinct. Yet, on a global scale, some Arctic animal populations may even benefit from a slightly warmer climate. It is also likely that less sea-ice cover will increase the overall phytoplankton production, which in turn should increase the total energy flow and production at higher trophic levels. Whatever the outcome, the implications of climate change and other anthropogenic influences should be carefully considered. Any climate change that influences the Arctic environment and its biodiversity will also have a major impact on local human populations. Biological diversity in the Arctic environment and indigenous cultures have been inextricably linked for millennia. Indigenous populations maintain a strong connection to the environment through their subsistence on natural resources and wildlife, and therefore rely on the integrity of the Arctic ecosystem and its biodiversity to survive.

Jorg Tews

See also Adaptation; Conservation; Environmental Problems; Food Chains

Further Reading

Chapin III, F.S. et al. (editors), Arctic and Alpine Biodiversity,

Berlin and New York: Springer, 1995 Conservation of Arctic Flora and Fauna (CAFF), Arctic Flora and Fauna: Status and Conservation, Helsinki: Edita, 2001 Hansell, Roger I.C. et al., "Atmospheric change and biodiversity in the Arctic." Environmental Monitoring and Assessment, 49 (1998): 303-325 Oechel, Walter C. et al. (editors), Global Change and Arctic Terrestrial Ecosystems, Berlin and New York: Springer, 1997

Pielou, E.C., A Naturalist's Guide to the Arctic, Chicago:

University of Chicago Press, 1994 Wielgolaski, F.E. (editor), Polar and Alpine Tundra, Amsterdam: Elsevier, 1997

BIODIVERSITY: RESEARCH PROGRAMS

Biodiversity is usually referred to as the variety of life on Earth. This variety is reflected at three levels: genetic diversity (diversity within species and their genetic composition), species diversity (the number of species), and ecosystem diversity (the species structure of ecosystems). Species diversity is important not only for providing ecosystem services such as food, fuel, fiber, and pharmaceuticals but also for our well-being in terms of recreation and tourism areas. The biodiversity or structure of ecosystems determines the function, health, and sustainability of ecosystems. A well-functioning biodiversity is thus an essential base on which to build sustainable development.

Many international strategies and policy instruments formulate overall goals for the conservation of biodiversity because there are currently many potential threats to biodiversity and we are possibly entering a major extinction event. A target for biodiversity was agreed for the first time at the global level at the Johannesburg World Summit on Sustainable Development (September 2002). This was to achieve a significant reduction in current loss of biological diversity by 2010.

Recent recognition of the importance of, yet decline in, global biodiversity has stimulated many programs dedicated to monitor changes in biodiversity or carry out research to understand the role of biodiversity in terms of ecosystem function and sustainable development. In the Arctic, there is particular concern about biodiversity changes because of current warming in many Arctic areas, projected amplification in the Arctic of future global warming, and other environmental changes such as increased habitat fragmentation (Nellemann et al., 2001). Past climate changes associated with deglaciation resulted in extinctions of many species and vegetation types in the Arctic: many large herbivores became extinct and vast tundra steppe regions became very restricted in area. The Arctic's biodiversity could be particularly sensitive to such changes because its flora and fauna are already poor in some groups of species, particularly those of the more advanced organisms (Matveyeva and Chernov, 2000).

Programs to measure biodiversity in the Arctic are numerous. They include local authority programs aiming to monitor target species, for example of conservation interest, indigenous peoples' projects seeking to understand changes in ecosystem services, national programs, focusing on inventorying of biodiversity and large regional (e.g., European Union) and international programs aiming to map and monitor circum-Arctic biodiversity. It is impossible to collate all these programs here: instead, we describe the development and fallout of some of the major programs of particular relevance to the Arctic. Many other programs exist, and some of them may have a minor Arctic component but these are outside our remit. In addition, we will not describe Arctic biodiversity or threats to it per se, information can be found in various sources, such as the Arctic Climate Impact Assessment (ACIA), Chapin and Korner (1995), Matveyeva and Chernov (2000), Vincent and Hobbie (2000), Sakshaug and Walsh (2000), and CAFF (2001).

A particular problem in presenting biodiversity programs is the separation of those that explicitly seek to assess the presence and absence of species and those that measure some aspect of the performance of species. Measurements of the performance of species include phenology, biomass, and population dynamics of animals. Such measurements give an indication of likely future changes in the abundance, presence, and absence of a species. We consequently include both types of program here.

Below we list the development and fallout of some of the major programs of particular relevance to the Arctic.

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