INFLUENCE OF CLIMATE ON IRRIGATION

The paper presents a procedure for estimating the influence of surface air temperature change on plant potential evapotranspiration and water supplies assuming rainfall and other climate parameters remain unchanged. On the basis of this procedure, it is estimated that 1 °C increase in temperature will produce an average annual increase in potential evapotranspiration in the western U.S. of about 40 mm. It also is estimated that the average annual runoff will decrease by about 6–8 percent for the same temperature increase, assuming no change in precipitation.If global temperatures increase, the spatial and temporal variabilities of climate are also expected to increase. Globally, rainfall is projected to increase, but the locations and extent of desert areas are expected to change. Weather is expected to become more extreme and variable. Water requirements in arid areas are projected to increase. Planning is needed to mitigate through improved management strategies the likely adverse effects of climatic ch...