The 'water-saving' effect of vegetation under rising CO₂ may be overestimated

Climate warming is intensifying terrestrial water scarcity and drought risks worldwide. Meanwhile, rising atmospheric CO2 reduces plant stomatal conductance—the openness of leaf pores that governs both CO2 intake and water loss—and improves water-use efficiency, which has been widely considered capable of alleviating land surface drying. However, a recent study reveals that this perceived benefit may have been optimistically overestimated.