Climate change will have major impacts on the availability of water for growing food and on crop productivity in the decades to come.
Climate Change, Water, and Food Security is a comprehensive survey of existing scientific knowledge on the anticipated consequences of climate change for water use in agriculture.
An acceleration of the world's hydrological cycle is anticipated as rising temperatures increase the rate of evaporation from land and sea. Rainfall will increase in the tropics and higher latitudes, but decrease in already dry semi-arid to mid-arid latitudes and in the interior of large continents. A greater frequency in droughts and floods will need to be planned for but already, water scarce areas of the world are expected to become drier and hotter.
Even though estimates of groundwater recharge under climate change cannot be made with any certainty, the increasing frequency of drought can be expected to encourage further development of available groundwater to buffer the production risk for farmers.
Increased temperatures will lengthen the growing season in northern temperate zones but will reduce the length almost everywhere else. Coupled with increased rates of evapotranspiration this will cause the yield potential and water productivity of crops to decline.
Issued by
(fao.org )