Meeting the ever-growing global demand for agricultural products while preserving our planet's limited freshwater resources poses an urgent and complex challenge. Climate change is projected to alter the timing, magnitude, and distribution of water resources, further complicating our ability to meet agricultural demand sustainably. We use integrated assessment models to evaluate the impacts of climate change on water and food systems at both global and regional scales. Considering freshwater availability as a major limiting factor, we assess crop production potential under a changing climate, while prioritizing sustainable water consumption for irrigation. Our approach aims to optimize water resources for agriculture, preserve environmental flows, and prevent depletion of freshwater stocks. We conducted two case studies to explore climate adaptation strategies for agriculture. The first case study examines the potential of irrigation expansion, water storage, and food waste reduction to enhance food self-sufficiency in African countries, using country-level data. The second case study employs high-resolution Earth system models to assess the vulnerability of California’s agricultural sector to shifting snow regimes in the Sierra Nevada mountains as the climate warms. We identify adaptation strategies to address challenges arising from earlier water availability and reduced runoff during peak irrigation demand due to the combined effects of increased rainfall, significant snowpack losses, and accelerated snow melt in the region. Overall, our research sheds light on the intricate dynamics impacting water and food security amid a changing climate, highlighting the importance of both global and regional analyses.