Evaluating water use efficiency and CO₂ absorption in plants under rising atmospheric carbon dioxide levels

Abstract

While elevated CO₂ levels have been shown to initially enhance photosynthesis, the long-term global effects on photosynthesis rates are influenced by a complex set of interacting factors. Although theoretical thresholds exist where further increases in CO₂ could potentially reduce photosynthesis, current research suggests that these levels remain far off. Contrary to recent reports suggesting a decline in water use efficiency (WUE) in plants, a review of the latest literature indicates that plants are, in fact, using water more efficiently while continuing to absorb atmospheric CO₂. This analysis highlights that rising CO₂ concentrations are contributing to improved WUE in plants, reflecting an adaptive response rather than a decline in functionality.