Diminishing CO2-driven gains in water-use efficiency of global forests

Nature Climate Change, Published online: 27 April 2020; doi:10.1038/s41558-020-0747-7 Under rising CO2, most plants constrict their stomata, lose less water via transpiration and photosynthesize more efficiently. A global dataset of tree-ring isotope measurements reveals a slowdown in water-use efficiency gains over the twentieth century, with marked spatiotemporal variability.