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 Development or developing may refer to: Arts *Development hell, when a project is stuck in development *Filmmaking, development phase, including finance and budgeting *Development (music), the process thematic material is reshaped * Photograph ...

of plant and animal life. Regions with arid climates tend to lack vegetation and are called

xeric Deserts and xeric shrublands are a biome defined by the World Wide Fund for Nature. Deserts and xeric (ancient Greek xērós, “dry") shrublands form the largest terrestrial biome, covering 19% of Earth's land surface area. Ecoregions in this h ...

or desertic. Most arid climates straddle the Equator; these regions include parts of

Africa Africa is the world's second-largest and second-most populous continent, after Asia in both cases. At about 30.3 million km2 (11.7 million square miles) including adjacent islands, it covers 6% of Earth's total surface area ...

Asia Asia (, ) is one of the world's most notable geographical regions, which is either considered a continent in its own right or a subcontinent of Eurasia, which shares the continental landmass of Afro-Eurasia with Africa. Asia covers an are ...

South America South America is a continent entirely in the Western Hemisphere and mostly in the Southern Hemisphere, with a relatively small portion in the Northern Hemisphere at the northern tip of the continent. It can also be described as the sout ...

, North America, and Australia.

Change over time

The distribution of aridity at any time is largely the result of the general circulation of the atmosphere. The latter does change significantly over time through

climate change In common usage, climate change describes global warming—the ongoing increase in global average temperature—and its effects on Earth's climate system. Climate change in a broader sense also includes previous long-term changes to ...

. For example, temperature increase by 1.5–2.1 percent across the

Nile Basin The Nile Basin is the part of Africa drained by the Nile River and its tributaries. Besides being the second largest hydrographic basin in Africa, the Nile Basin is effectively the most notable drainage basin on the continent. It covers approxi ...

over the next 30–40 years could change the region from

semi-arid A semi-arid climate, semi-desert climate, or steppe climate is a dry climate sub-type. It is located on regions that receive precipitation below potential evapotranspiration, but not as low as a desert climate. There are different kinds of semi- ...

to arid, significantly reducing the land usable for

agriculture Agriculture or farming is the practice of cultivating plants and livestock. Agriculture was the key development in the rise of sedentary human civilization, whereby farming of domesticated species created food surpluses that enabled people t ...

. 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