Ecosystems

World deserts

Deserts extend from the 20th northern parallel to the 20th southern parallel. 15% of all lands above sea level are considered medium dry, another 15% dry and 4% extremely dry. Extremely dry deserts have no rainfalls at all for periods of over one year. This is typical of real deserts, such as the Sahara, part of the Arabic desert; the Mojave desert in North America; the Namibian desert and part of the Kalahari; the Atacama desert in Latin America; the Gobi desert in Asia and part of the Australian desert. Dry and medium dry deserts, with comparatively more abundant rainfalls and shorter droughts, include part of the Kalahari and the Karoo desert in South-Africa; in Asia, the Arabic and Middle Eastern desert, the Iranian desert, the Touran, the Indian, Tibetan and Mongolian desert; in North America, the Mexican Chihuahua desert; the Patagonian desert in Latin America and a large part of the Australian desert.