They also store the biological diversity necessary for the sustainability of human life. Mountain environments are essential to the survival of global ecosystems. Mountain ecosystems are also fragile. They are susceptible to soil erosion, landslides, and loss of genetic diversity. Physical isolation has excluded the mountains and their populations from development, resulting in political and economic marginality.
Mountain people suffer from unemployment, poverty, poor health, and insufficient sanitation.
In contrast to popular perceptions, however, some mountain areas have not only improved their economies radically, but they have also preserved their environments, biodiversity, and cultural heritage. It is essential to learn from successes as well as from failures. Among the world's mountain areas, Asia contains the largest, highest, and most populated mountain systems. More than 200 million people live in mountain and upland areas. Another one billion people downstream are affected by mountain conditions.