The Arctic and Antarctic regions represent the world's largest remaining natural areas and pristine environments. Polar regions have long been recognized as important indicators of the planet's overall health, especially with regard to global warming, long-range transport of pollutants, and, in the case of Antarctica, atmospheric ozone concentrations. For these reasons, universal concern generated international action regarding the state of the environment in both regions. In the Arctic, overexploitation of fisheries, mining, the presence of forest industries, and infrastructure development all threaten natural habitats and open the possibility for direct degradation and pollution of resources. A fragile ecosystem, the region is particularly sensitive to land degradation and erosion.
Biodiversity is also fragile, with few but highly specialized and adapted species.
Military and industrial interest in the Arctic has had a negative impact through dumping of radioactive wastes and accidents involving similar materials. While radioactivity of Arctic seas is low compared with other north European seas, it is still considered one of the main threats to the Arctic environment. Traditional societies have also increased their exploitation of resources through a shift towards non-traditional activities. The vast extent of Antarctica's sea ice and continental ice sheet are especially important with regard to the modelling and assessment of climate change and sea level rise. Its unique geographical location and pristine environment also enable the monitoring of air pollution against a background of minimum interference and high sensitivity to change.