Maintaining a stable water supply for agriculture requires both demand-side strategies, such as recycling and conserving water, and supply-side strategies, such as water storage.

Thornton et al., 2012

Arne Hoel, World Bank

Extra facts

  • On the demand-side, water-use efficiency, through, for example, recycling water, is the main adaptation intervention. Greater use of economic incentives, including metering and pricing, can encourage water conservation and the reallocation of water to highly-valued uses (IWMI 2007).
  • On the supply-side, more strategic water storage is a key intervention for the adaptation of agriculture to climate change. Water storage provides a buffer and can offset the risks associated with floods or droughts. Water storage options include reservoirs, ponds, tanks, aquifers, soil moisture and natural wetlands. (McCartney and Smakhtin 2010).
  • The rate of glacier deposition and melting under climate change will be a major determinant of water availability for agriculture, but remains highly uncertain and under-studied. In China, for example, the best current knowledge is that runoff from glaciers may peak from 2030 to 2050, followed by a gradual decline (Piao et al. 2010).
  • Irrigation will be an important adaptation option in some regions. It compensates both for long-term declines in water supply and for short-term deficits associated with increasing climate variability. This will be key for Brazil, for example (Rosenzweig et al. 2004; Cunha et al. 2012).
  • Irrigation will not work as an adaptation option everywhere. In sub-Saharan Africa, water supply reliability (ratio of water consumption to requirements) is expected to worsen and will limit the adaptation potential of irrigation. Even farming regions that are expected to have sufficient water under climate change, such as the Danube basin of Europe, may not be able to expand irrigation for adaptation strategy, as models suggest that this would increase water supply unreliability (Rosenzweig et al. 2004).
  • Climate change mitigation measures, such as reafforestation, can assist adaptation by increasing the capacity of soils and landscapes to hold water (Thornton et al. 2012).
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Methods, caveats and issues

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Sources

  • Thornton P, Cramer L, eds. 2012. Impacts of climate change on the agricultural and aquatic systems and natural resources within the CGIAR’s mandate. CCAFS Working Paper 23. Copenhagen, Denmark: CGIAR Research Program on Climate Change, Agriculture and Food Security (CCAFS). (Available from http://cgspace.cgiar.org/handle/10568/21226)
  • Cunha D, Coelho A, Feres J, Braga M. 2012. Impacts of climate change on Brazilian agriculture: an analysis of irrigation as an adaptation strategy. No 126223. Foz do Iguacu, Brazil: International Association of Agricultural Economists (IAAE). (Available from http://purl.umn.edu/126223)
  • [IWMI] International Water Management Institute. 2007. Water: key for adapting to climate change. Colombo, Sri Lanka: International Water Management Institute. (Available from http://www.iwmi.cgiar.org/publications/Other/PDF/ClimateChangeFlyer.pdf)
  • McCartney M, Smakhtin, V. 2010. Water storage in an era of climate change: addressing the challenge of increasing rainfall variability. Colombo, Sri Lanka: International Water Management Institute (IWMI). (Available from http://www.iwmi.cgiar.org/Publications/ Blue_Papers/PDF/Blue_Paper_2010-final.pdf)
  • Piao S, Ciais P, Huang Y, Shen Z, Peng S, Li J, Zhou L, Liu H, Ma Y, Ding Y, Friedlingstein P, Liu C, Tan K, Yu Y, Zhang T, Fang J. 2010. The impacts of climate change on water resources and agriculture in China. Nature 467(7311):43-51.
  • Rosenzweig C, Strzepek KM, Major DC, Iglesias A, Yates DN, McCluskey A, Hillel D. 2004. Water resources for agriculture in a changing climate: international case studies. Global Environmental Change 14:345–360.
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