Climate change and variability threatens the sustainability of future food productions, especially in semi-arid regions where water resources are limited, and irrigated agriculture is widespread. Increasing temperatures will exacerbate evaporative losses and increase plant water needs. Consequently, higher irrigation intensities would be a logical measure to mitigate climate change impacts in these regions. Using an ensemble of well-parameterized crop model simulations, we show that this mitigation measure is oversimplified and that besides water resources availability, strong temperature increases play a crucial role in crop developments and resulting plant water needs. Our analysis encompasses agricultural areas of the Lower Chenab Canal System in Pakistan (15 000 km²), which is part of the Indus River irrigation system, the largest irrigation system in the world; and covers economically important crop growing areas (e.g., of cotton, rice and maize crops). Climate models project an above average increase in temperature over the study region, and the agro-hydrological and biophysical crops models respond with a strong decline of up to -24% (±12%) in future crop productions. Our modeling results further suggest that evaporative and irrigation demands do not align with increasing future temperature trends. The resulting decline in crop productions is consistent among model projections despite an intensification of irrigation measures and the positive effect of future CO₂ enrichments. Overall, our study emphasizes the role of elevated temperature stress, its effects on agricultural production as well as water demand, and its implications for climate change adaption strategies to mitigate adverse impacts in an intensively irrigated region.