
Aridity is the condition of geographical regions which make up approximately 43% of total global available land area, characterized by low annual precipitation, increased temperatures, and limited water availability.
[Perez-Aguilar, L. Y., Plata-Rocha, W., Monjardin-Armenta, S. A., Franco-Ochoa, C., & Zambrano-Medina, Y. G. (2021). The Identification and Classification of Arid Zones through Multicriteria Evaluation and Geographic Information Systems—Case Study: Arid Regions of Northwest Mexico. ''ISPRS International Journal of Geo-Information'', ''10''(11), 720. https://doi.org/10.3390/ijgi10110720] These areas tend to fall upon degraded soils, and their health and functioning are key necessities of regulating ecosystems’ atmospheric components.
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 gases that envelop an astronomical object, held in place by the gravity of the object. A planet retains an atmosphere when the gravity is great and the temperature of the atmosphere is low. A stellar atmosph ...
. The latter does change significantly over time through
climate change
Present-day climate change includes both global warming—the ongoing increase in Global surface temperature, global average temperature—and its wider effects on Earth's climate system. Climate variability and change, Climate change in ...
. 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.
A December 2024 report from the
UNCCD concluded that more than three-quarters of the Earth's land "has become permanently dryer in recent decades", that "drier climates now affecting vast regions across the globe will not return to how they were", and that a quarter of the global population lives in expanding drylands.
See also
*
Arid Forest Research Institute
*
Aridity index
*
Desiccation tolerance
*
Drought
*
Humidity
*
Vapor pressure
References
External links
* 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
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Climate patterns
Soil science
Water scarcity