A natural habitat is an area of nature, usually a unique self-contained ecosystem, that supports a selection of plants and animals indigenous to the region which are adapted both to the climate and living systems there, and exist in some sort of permanently sustainable balance. Undisturbed habitat ecosystems are becoming increasingly rare, as invasive species are introduced via human travel patterns, and due to encroachment by urban development, pollution, and the construction of infrastructure such as roads, bridges, pipelines, mining, and ranching projects. Protected habitat locations around the globe are seen as vital to preserving the diversity of species.
International conservation movements recognize 142 different categories of natural habitat, known as global ecoregions, 53 freshwater and 43 marine environments. These range from tropical forests and coral reefs that support a thriving, wide variety of plant and animal species, to tundras and deserts that support a hardier, yet smaller diversity of indigenous organisms. Together these interlocking natural habitat environments are seen as a web of life on Earth that must be preserved to some minimum degree so that the loss of one ecoregion does not directly or indirectly cause the collapse of others as well.
Protection of the environment, whether it is an undisturbed habitat, requires habitat restoration, or an endangered animal's natural habitat, is being carried out by a wide variety of private, public, and global governmental organizations. Activity has become so diverse in the desire to preserve natural habitat as a counter to human expansion, that it has taken on the form of a international social movement. This culminated in 1972 with the formation of the United Nations Environment Programme (UNEP) at a conference in Stockholm, Sweden, attended by 114 nations. Follow-up conferences were held in 1992 by the UN, and later by European Union and North American groups of nations. In 1988, the formation of the Intergovernmental Panel on Climate Change (IPCC) was also created to investigate human activity that contributes to rapid climate change, which can have serious detrimental effects on the ability of any natural habitat to adapt and survive.