Sustainable global irrigation expansion could support only two-thirds of croplands under 1.5 °C and 3 °C warming

As climate warming exacerbates heat stress, promoting irrigation as a climate adaptation strategy can mitigate adverse impacts on agricultural productivity. Here we use global crop and irrigation datasets in conjunction with climate models to show that sustaining wheat, maize, rice and barley production under 1.5 °C and 3 °C warming scenarios-aligned with current climate targets and business-as-usual projections-requires 13% (25 Mha) and 47% (94 Mha) global irrigation expansion, respectively. Notably, only 60% of these croplands can support irrigation without generating water scarcity and depleting local freshwater resources. These findings underscore the urgency of limiting global warming within 1.5 °C and reveal unequal adaptation needs worldwide between warming scenarios. Our work identifies at high resolution areas where and to what extent irrigation can promote climate-resilient agriculture.