Conceptualizing the climate change perspective of crop growth and evapotranspiration (ET_c) rates and subsequent irrigation water requirements (IWR) is necessary for sustaining the agriculture sector and tackling food security issues in Pakistan. This article projects the future growth periods and water demands for the wheat-rice system of Punjab. Intense and hotter transitions in the future thermal regimes and erratic monsoon rainfall increments were envisaged. The crop growth rates were accelerated by the probable temperature rise resulting in shortened growth periods. The temperature rise increased the reference evapotranspiration rates; however, the future ET_c declined due to reduced growth period and net radiation. Highly unpredictable, but mostly increasing, cumulative seasonal and annual rainfalls were indicative of more effective rainfalls during the future crop seasons. Reduced ET_c and increments in seasonal effective rainfalls gave rise to the declining IWR for both crops. The study findings seemingly undermined the harmful climate change influences on the water requirements of the wheat-rice system of Punjab but alarmingly shortening of growth periods indicates a higher crop failure tendency under the projected future thermal regime.

将作物生长和蒸发蒸腾 ( ET _c ) 率以及随后的灌溉用水需求 (IWR)的气候变化视角概念化对于维持巴基斯坦的农业部门和解决粮食安全问题是必要的。本文预测了旁遮普省小麦-水稻系统的未来生长期和需水量。设想了未来热状态和不稳定的季风降雨增量的强烈和更热的转变。可能的温度升高导致作物生长速度加快，导致生长期缩短。温度升高增加了参考蒸散率；然而，未来的ET _c由于生长期减少和净辐射下降。季节性和年度累积降雨量极难预测，但大多在增加，这表明未来作物季节的降雨量将更加有效。ET _{c 的}减少和季节性有效降雨的增加导致两种作物的 IWR 下降。研究结果似乎削弱了气候变化对旁遮普小麦-水稻系统需水量的有害影响，但令人震惊的是，生长期的缩短表明在预计的未来热状况下作物歉收的趋势更高。