Climate change poses a major challenge to crop production in semi-arid regions, where limited water availability is a critical constraint. Understanding how climate change influences crop productivity is essential for developing practical adaptation and mitigation strategies. The objectives of this study were to assess the effects of climate change on crop yields and identify sustainable cotton-based cropping systems under projected climate scenarios. The Decision Support System for Agrotechnology Transfer (DSSAT) was applied to simulate yields of cotton, sorghum and wheat across three cotton-based cropping systems in the Texas High Plains under three shared socioeconomic pathway (SSP) climate scenarios. Simulations were conducted at the soil-type levels to assess crop-specific and spatial yield responses for the 21st century. Results showed heterogeneous yield responses across crops, cropping systems and climate scenarios. Cotton yield was projected to increase by 3.4%-15.6% under the low- and medium-emission scenarios (SSP1-2.6 and SSP2-4.5), reflecting the effects of moderate warming and elevated atmospheric CO2 concentrations. In contrast, cotton yield declined under the high-emission (SSP5-8.5) scenario (4.1%-16.8%), driven by temperatures exceeding optimal thresholds for crop growth. Sorghum yield showed greater sensitivity to warming, with noticeable declines under SSP5-8.5, particularly in the mid- and late-century periods as CO2 fertilisation effects approach saturation under current climatic conditions. Wheat yield increased slightly or remained stable under SSP1-2.6 and SSP2-4.5 but declined slightly under SSP5-8.5, especially toward the late century. Spatial analyses revealed substantial variability in yield responses across counties. Northern and central counties generally maintained stable or improved yields under moderate emission scenarios, whereas southern and western counties experienced greater yield declines under SSP5-8.5. Among cropping systems, the cotton-sorghum rotation consistently produced higher and more stable cotton yields than continuous cotton and cotton-wheat systems, indicating greater resilience under projected climate change scenarios.