right|220px|thumb|Arid regions of the Western United States as mapped in 1893

Aridity is a condition of geographical regions characterized by low annual precipitation, increased temperatures, and limited water availability. These areas, which make up approximately 43% of total global available land area, tend to fall upon degraded soils, and their health and functioning are key necessities of regulating ecosystems’ atmospheric components.

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

  • 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