1893 Arid regions of the western united states

A region is arid when it severely lacks available water, to the extent of hindering or preventing the growth and development of plant and animal life. Regions with arid climates tend to lack vegetation and are called xeric or

desert A desert is a barren area of landscape where little precipitation occurs and, consequently, living conditions are hostile for plant and animal life. The lack of vegetation exposes the unprotected surface of the ground to denudation. About on ...

ic. Most arid climates straddle the

Equator The equator is a circle of latitude, about in circumference, that divides Earth into the Northern and Southern hemispheres. It is an imaginary line located at 0 degrees latitude, halfway between the North and South poles. The term can als ...

; these regions include parts of Africa, Asia, South America,

North America North America is a continent in the Northern Hemisphere and almost entirely within the Western Hemisphere. It is bordered to the north by the Arctic Ocean, to the east by the Atlantic Ocean, to the southeast by South America and the Car ...

, and

Australia Australia, officially the Commonwealth of Australia, is a Sovereign state, sovereign country comprising the mainland of the Australia (continent), Australian continent, the island of Tasmania, and numerous List of islands of Australia, sma ...

Change over time

The distribution of aridity at any time is largely the result of the general circulation of the

atmosphere An atmosphere () is a layer of gas or layers of gases that envelop a planet, and is held in place by the gravity of the planetary body. A planet retains an atmosphere when the gravity is great and the temperature of the atmosphere is low. A s ...

. The latter does change significantly over time through climate change. For example, temperature increase by 1.5–2.1 percent across the Nile Basin over the next 30–40 years could change the region from semi-arid to arid, significantly reducing the land usable for agriculture. In addition, changes in land use can increase demands on soil water and thereby increase aridity.

References

* Griffiths, J. F. (1985) 'Climatology', Chapter 2 in ''Handbook of Applied Meteorology'', Edited by David D. Houghton, John Wiley and Sons, . * Durrenberger, R. W. (1987) 'Arid Climates', article in ''The Encyclopedia of Climatology'', p. 92–101, Edited by J. E. Oliver and R. W. Fairbridge, Van Nostrand Reinhold Company, New York, . * Stadler, S. J (1987) 'Aridity Indexes', article in ''The Encyclopedia of Climatology'', p. 102–107, Edited by J. E. Oliver and R. W. Fairbridge, Van Nostrand Reinhold Company, New York, .
Blue Peace for the Nile Report
2009, Strategic Foresight Group Climate patterns Soil science Water scarcity {{climate-stub

Change over time

See also

References