Mountains: globally important ecosystems
Martin F. Price leads the Mountain Regions Programme at the Environmental Change Unit, University of Oxford, UK.
An overview of the importance of mountains in sustainable development and their place on the global political agenda.
Mountain ecosystems are found throughout the world, from the equator almost to the poles, occupying approximately one-fifth of its land surface. Beyond their common characteristics of having high relative relief (or very marked topographic variation) and steep slopes, mountains are remarkably diverse (Ives. Messerli and Spiess, 1997). They are found on every continent, and at every altitude, from close to sea level to the highest place on the earth - the summit of Mount Everest (Sagarmatha or Qomolangma) on the border between Nepal and the Tibet Autonomous Region of China.
Half of the world's population depends on mountain water
An estimated one-tenth of the human population derive their life-support directly from mountains. Yet, mountains are important not only for their inhabitants, but for millions of people living in lowlands. At the global scale, mountains' greatest value may be as sources of all the world's major rivers, and many smaller ones (Mountain Agenda, 1998). Mountains play a critical role in the water cycle by capturing moisture from air masses; when this precipitation falls as snow, it is stored until it melts in the spring and summer, providing essential water for settlements, agriculture and industries downstream - often during the period of lowest rainfall. In semi-arid and arid regions, over 90 percent of river flow comes from the mountains. Even in temperate Europe, the Alps that occupy only 11 percent of the area of the Rhine river basin supply 31 percent of the annual flow - and in summer more than 50 percent.
Mountain water is also a source of hydroelectric power, most of which is used on the plains below. Historically, water...