A variety of factors threaten water supplies in deserts.
Approximately one-quarter of the Earth's land surface is desert. Although most people may think the world's deserts are indomitable, in 2011 much of the Earth's deserts are facing increasing pressures and strains. According to a 2006 UN Environment Program (UNEP) report, "countries like Saudi Arabia, Pakistan, western China, Chad, Iraq, Niger and Syria will be particularly affected."
Climate Change
Similar to other geographic regions of the Earth, climate change threatens many desert areas of the world. According to a 2006 report by UNEP, between 1976 and 2000 average world temperatures increased by 0.45 degrees Celsius; however, desert temperatures increased at a higher rate, between 0.5 and 2 degrees Celsius. This temperature increase means glaciers are receding and less water is destined for desert regions. In fact, scientists expect rainfall to decrease by 10 to 20 percent by the end of the 21st century in desert regions.
Depletion of Groundwater
Another serious problem facing the world's deserts is the overexploitation of groundwater. As cities and towns push further into or around deserts, the human population uses more of the local groundwater for irrigation or drinking. The 2006 UNEP report states that "increasingly dry rivers, inefficient water use such as irrigation, and population growth will all add to water shortages in deserts ... deserts' groundwater levels are dropping 'very, very quickly' as ancient underground aquifers become exhausted." As this happens it threatens the habitats of the surrounding desert plants and animals.
Reduction in Land Area
The increasing human population across the globe requires more land. The spread of residential, commercial, agricultural and industrial areas threatens to reduce the amount of desert land. Because of its extreme condition, a desert is usually a fragile ecosystem. The introduction of roads, housing units, golf courses or farming areas depletes the land area of deserts, as well as reduces the ecosystems of animals and plants.
Cultural Diminution
As developed nations grow and progress further into desert regions, local cultures face pressure as well. For instance, in the United States, the westward expansion of the U.S. population greatly diminished the numbers and culture of the Native Americans who lived in desert regions, such as the Mojave. Irreplaceable artifacts, such as ancient lithographs left behind by Native Americans, risk destruction at the encroachment of cities and civilization. Other areas of the world also face this problem.
