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FACTS AND FIGURES ABOUT DRYLANDS Drylands, as defined by the UNCCD, encompass the arid, semi-arid, and dry sub-humid zones. In these zones, ratios of mean annual precipitation to mean annual precipitation to potential evapotranspiration range from 0.05 to 0.65 (excluding polar and sub-polar regions). Drylands occupy 41% of the earth’s land area and are inhabited by over 2 billion people worldwide. Drylands are found in all continents, except for Antarctica. Australia, the United States, the Russian Federation, China and Kazakhstan are the countries with the most extensive drylands. 40% of people in Africa, South America and Asia live in drylands. Drylands do not include the true deserts of the world, such as the Sahara and the Kalahari. Deserts are harsh environments with little productive potential. Few people live in deserts, and those who do, live there for only short periods of time. Drylands are generally subject to climate regimes that are not highly favourable to crop production. Low total rainfall and high variability in rainfall patterns present difficult challenges for growing crops. Desertification is the degradation of drylands. It involves the loss of biological or economic productivity and complexity in croplands, pastures and woodlands. It is due mainly to climate variability and unsustainable human activities. 70% of the world's drylands (excluding hyper-arid deserts), or some 3,600 million hectares, are degraded. A major part of the poor people in the world live in arid areas and depends directly on adjacent natural resources, including water, for their livelihoods. Many dryland inhabitants are self-subsistent small scale farmers who also have some livestock. For them, retaining as much water as possible is a question of survival, yet in arid areas, a substantial amount of rainwater is lost through surface run-off, evaporation and percolation.
Information from: Source: UNESCO Water Portal, September 2005
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