Arid area
The worldwide distribution of non-polar arid areas from 1961 to 1990 according to the UNEP climate index: 51 million km² (41% of the land surface), habitat for more than 1/3 of humanity. By the end of the 21st century, the area is expected to grow to 58 million km².
A dry area is a natural geographical region with small amounts of water in the soil . In general, such an area is characterized by little, seasonally variable rainfall , extreme air temperatures and high potential evapotranspiration . For quantitative purposes, dry areas are defined as those regions in which the aridity index from the ratio of the annual precipitation height (in mm) to the potential evapotranspiration (in mm) does not exceed 0.65.
Individual evidence
- ^ NJ Middleton, DSG Thomas: World Atlas of Desertification: United Nations Environmental Program. Arnold, 1992.
- ↑ Fernando T. Maestre, Roberto Salguero-Gómez, José L. Quero: It is getting hotter in here: determining and projecting the impacts of global environmental change on drylands. In: Philosophical Transactions of the Royal Society of London B: Biological Sciences. 367.1606, 2012, pp. 3062-3075. (on-line)
- ^ A b S. Feng, Q. Fu: Expansion of global drylands under a warming climate. In: Atmos. Chem. Phys. 13, 2013, pp. 10081-10094. doi: 10.5194 / acp-13-10081-2013 . ( PDF )
- ↑ Reynolds, James F., et al. "Natural and human dimensions of land degradation in drylands: causes and consequences." Terrestrial ecosystems in a changing world (2007): 247-257. ( PDF )
- ↑ Lal, rattan. "Carbon sequestration in dryland ecosystems." Environmental management 33.4 (2004): 528-544. ( PDF )