Some human systems also are unique and threatened by climate change. These tend to be poor and isolated communities that are tied to specific locations or ecosystems. Among the unique and threatened human systems are some small island states and indigenous communities.

19.3.4.1. Threatened Small Island States

Because of their low elevation and small size, many small island states are threatened with partial or virtually total inundation by future rises in sea level. In addition, increased intensity or frequency of cyclones could harm many of these islands. The existence or well-being of many small island states is threatened by climate change and sea-level rise over the next century and beyond.

Many small island states—especially the atoll nations of the Pacific and Indian Oceans—are among the most vulnerable to climate change, seasonal-to-interannual climate variability, and sea-level rise. Much of their critical infrastructure and many socioeconomic activities tend to be located along the coastline—in many cases at or close to present sea level (Nurse, 1992; Pernetta, 1992; Hay and Kaluwin, 1993). Coastal erosion, saline intrusion, sea flooding, and land-based pollution already are serious problems in many of these islands. Among these factors, sea-level rise will pose a serious threat to the ecosystems, economy, and, in some cases, existence of many small island states. It is estimated that 30% of known threatened plant species are endemic to such islands, and 23% of bird species found on these islands are threatened (Nurse et al., 1998). Projected future climate change and sea-level rise will lead to shifts in species composition (see Chapter 17).

Many small island nations are only a few meters above present sea level. These states may face serious threat of permanent inundation from sea-level rise. Among the most vulnerable of these island states are the Marshall Islands, Kiribati, Tuvalu, Tonga, the Federated States of Micronesia, and the Cook Islands (in the Pacific Ocean); Antigua and Nevis (in the Caribbean Sea); and the Maldives (in the Indian Ocean). Small island states may face the following types of impacts from sea-level rise and climate change (Gaffin, 1997; Nurse et al., 1998):

• Increased coastal erosion
• Changes in aquifer volume and water quality with increased saline intrusion
• Coral reef deterioration resulting from sea-level rise and thermal stress
• Outmigration caused by permanent inundation
• Social instability related to inter-island migration
• Loss of income resulting from negative effects on tourist industry
• Increased vulnerability of human settlement due to decrease in land area
• Loss of agriculture and vegetation.

Gaffin (1997) concludes that without planned adaptation, the vulnerabilities of small island states are as follows:

• An 80-cm sea-level rise could inundate two-thirds of the Marshall Islands and Kiribati.²
• A 90-cm sea-level rise could cause 85% of Male, the capital of the Maldives, to be inundated (Pernetta, 1989).

19.3.4.2. Indigenous Communities

Indigenous people often live in harsh climatic environments to which their culture and traditions are well adapted. Indigenous people generally have low incomes and inhabit isolated rural environments and low-lying margins of large towns and cities. Therefore, they are more exposed to social problems of economic insecurity, inadequate water supplies, and lower health standards (see Section 15.3.2.8). These inadequacies in social safety nets indeed put them at greater risk of climate-related disasters and their effects.

For many reasons, indigenous communities are unique and threatened by climate change. First, they are more vulnerable to climate-related disasters such as storms, floods, and droughts because of inadequate structural protection measures and services, as well as to any increase in the prevalence of pests and diseases—especially vector-borne, respiratory, or otherwise infectious diseases (Woodward et al., 1998; Braaf, 1999). Second, their lifestyles are tied to current climate and vegetation and wildlife. Third, changes in current climate could threaten these lifestyles and would present these peoples with difficult choices concerning their future.

Native peoples in the Mackenzie basin in Canada are an example of an indigenous community that is threatened by climate change (Cohen 1994, 1996, 1997a,b,c). The Mackenzie basin is a watershed that extends from the mid-latitudes to the subarctic in northwest Canada. Over the past 35 years, the area has been experiencing a rapid temperature increase of about 1°C per decade. The changes in temperature also are changing the landscape of the basin as permafrost melts, landslides and forest fires increase, and water levels are lowered.

For the native people in the basin, wildlife is the important natural resource; it is harvested by hunting, fishing, and trapping. It is critically important in economic terms—primarily as a source of food, income, and traditional clothing—but inseparable from the cultural importance for maintaining traditional systems of knowledge and identity (Pinter, 1997). As noted, changes in the climate in the basin would have substantial impacts on water resources and vegetation. Changes in forest fire frequencies would lead to cumulative impacts on wildlife, including terrestrial, aquatic, and bird species. For example, because of a decrease in water availability, muskrats already have disappeared from the Peace Athabasca delta (Pinter, 1997). In this area, trapping once was a major industry, but this economic activity has now disappeared. Thus, changes in ecosystem resource bases will have direct impacts on native lifestyles in the Mackenzie basin (Cohen et al., 1997a).

Some important changes are expected in native lifestyles in the Mackenzie Basin regardless of climate change. For example, an increasing number of people will seek their livelihoods in the wage economy, and migration to other areas will intensify. These changes could result in a decline in cultural values and heritage that are thousands of years old. If climate change adversely affects the lifestyle of the indigenous community, this decline could be accelerated.

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