Simulating crop water consumption has been introduced as a valuable decision tool in food security. Such a tool is typically used to support a better understanding of how to increase water-use efficiency to satisfy optimal water management and sustainability. However, climate change is one of the most important and influential factors that restrain sustainable development, agriculture, and food security. Wheat is one of the most important and strategic products in the world and Iran. Therefore, in this study, the impacts of future climate changes on winter wheat yield, water requirement (WR), evapotranspiration (ET), and water footprint (WF) were evaluated in Qazvin Plain, Iran. As such, the outputs from five general circulation models (EC-EARTH, GFDL-CM3, MPI-ESM-MR, MIROC5, and HADGEM2-ES) were fed into the LARS-WG model to get finer spatial climate data for four future periods (P1:2021–2040, P2:2041–2060, P3:2061–2080, P4:2081–2100) considering three emission scenarios (RCP2.6, RCP4.5, and RCP8.5). Thereafter, the projected climate change data were used in the FAO AquaCrop model to simulate the variability of wheat characteristics. The results proved the superiority of LARS-WG to model the maximum and minimum temperatures and precipitation (P) of the baseline scenario (1986–2015). Moreover, results revealed that the wheat WF will decrease in future periods. The modeling results showed that the average wheat yield and biomass will increase in future periods by 7.67 and 15.98 tons/ha, respectively, as compared to the baseline. The highest increase was recorded by the HadGEM2-ES model with RCP8.5 during 2081–2100. The average WR in the baseline was 127.14 mm, which was projected to decrease in future periods. The results show that ET will potentially increase in the period 2021–2040. As a consequence, the adapted methodology produced significantly superior outcomes and can aid in decision-making for both water managers and development planners.

模拟作物用水量已成为粮食安全中一种有价值的决策工具。此类工具通常用于支持更好地了解如何提高用水效率以满足最佳水管理和可持续性。然而，气候变化是制约可持续发展、农业和粮食安全的最重要和最有影响力的因素之一。小麦是世界和伊朗最重要和最具战略意义的产品之一。因此，在本研究中，评估了未来气候变化对伊朗加兹温平原冬小麦产量、需水量 （WR）、蒸散量 （ET） 和水足迹 （WF） 的影响。因此，将五个环流模式（EC-EARTH、GFDL-CM3、MPI-ESM-MR、MIROC5 和 HADGEM2-ES）的输出输入到 LARS-WG 模型中，以获得未来四个时期（P1：2021-2040、P2：2041-2060、P3：2061-2080、P4：2081-2100）的更精细空间气候数据考虑到三种排放情景（RCP2.6、RCP4.5 和 RCP8.5）。此后，将预测的气候变化数据用于 FAO AquaCrop 模型，以模拟小麦特性的变异性。结果证明了 LARS-WG 在模拟基线情景 （1986-2015） 的最高和最低温度和降水 （P） 方面的优越性。此外，结果表明小麦 WF 在未来一段时间内将下降。建模结果表明，与基线相比，未来一段时间小麦的平均产量和生物量将分别增加 7.67 和 15.98 吨/公顷。在 2081-2100 年期间，具有 RCP8.5 的 HadGEM2-ES 模型记录了最高的增长。基线中的平均 WR 为 127.14 毫米，预计在未来一段时间内会下降。 结果表明，ET 在 2021-2040 年期间可能会增加。因此，调整后的方法产生了明显卓越的结果，可以帮助水资源管理者和开发规划者做出决策。