Climate change will impact crop production in Western Canada by modifying growing season conditions. Precipitation pattern changes and warmer temperatures will pose significant risks to crops. Studies have shown that multivariable agroclimatic indices can enhance climatic impact assessment on crop production. This study uses multivariable agroclimatic indices to assess how climate change may impact crop production in western Canada by the end of the 21st century. We use convection-permitting regional climate simulations for the current (CTL) and future climate under the Representative Concentration Pathway 8.5 scenario (RCP8.5) scenario based on the pseudo-global warming (PGW) approach to assess the impact of the climate on growing season indices. CTL and PGW are bias-corrected to the Global Environmental Multiscale (GEM) Canadian Precipitation Analysis (CaPA) (GEM-CaPA) dataset using the multivariate quantile mapping method. Our study analyses Effective Precipitation (Pe), Temperature Humidity Index (THI), and Precipitation Intensity Index (PII) at seasonal and sub-seasonal scales as they apply to cool-season crops. The CTL simulation shows a good performance in reproducing the spatial patterns and the temporal variability of the selected indices in western Canada. Results show that precipitation (Effective Precipitation) will decrease by over 60 mm (40 mm), rainy days will decrease by up to 10 days, and precipitation intensities will increase across western Canada. Warming will lead to THI unit increases of about 3.5 (>5) in the prairies (northeastern parts of western Canada in June). This study’s findings can be useful in generating appropriate information to inform policy on adaptation for sustainable crop production by the end of the 21st century.

气候变化将通过改变生长季节条件影响加拿大西部的农作物生产。降水模式的变化和气温升高将对农作物造成重大风险。研究表明，多变量农业气候指数可以加强气候对作物生产的影响评估。本研究使用多变量农业气候指数来评估到 21 世纪末气候变化可能如何影响加拿大西部的农作物生产。我们使用基于伪全球变暖（PGW）方法的代表性浓度路径8.5情景（RCP8.5）情景下的当前（CTL）和未来气候的允许对流区域气候模拟来评估气候对生长的影响季节指数。使用多元分位数映射方法对 CTL 和 PGW 对全球环境多尺度 (GEM) 加拿大降水分析 (CaPA) (GEM-CaPA) 数据集进行偏差校正。我们的研究分析了季节性和次季节尺度的有效降水量 (Pe)、温度湿度指数 (THI) 和降水强度指数 (PII)，因为它们适用于冷季作物。CTL 模拟在再现加拿大西部所选指数的空间模式和时间变化方面表现出良好的性能。结果显示，加拿大西部地区降水量（有效降水量）将减少超过 60 毫米（40 毫米），雨天数将减少多达 10 天，降水强度将增加。变暖将导致草原地区（6 月加拿大西部东北部地区）THI 单位增加约 3.5 (>5)。这项研究的结果有助于生成适当的信息，为 21 世纪末可持续作物生产的适应政策提供信息。