Aerial view of a forest.
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Editors’ Highlights are summaries of recent papers by AGU’s journal editors.
Source: AGU Advances

Leaf area index, which measures the ratio of leaf area to ground area, is commonly used by researchers to track foliage coverage and ecosystem health. One consequence of global warming, observed by satellite remote sensing, has been a long-term increase in leaf area index. This Earth “greening” is predicated on increased terrestrial carbon uptake under increasing CO2.

Chang et al. [2026] examine water controls on vegetation greening by isolating structural (e.g. leaf area index, LAI) and physiological (e.g., water use efficiency, WUE) impacts under increasing CO2. Their analysis shows worldwide patterns of increased plant water stress (PWS) and ecological drought, attributed to soil moisture, atmospheric aridity, and regional climate. This study demonstrates water limits on Earth greening emerging from local interdependencies between the carbon and water cycles. 

Attribution of variables, including meteorological factors (air temperature, Ta; and net radiation, Rn), soil and atmospheric aridity (VPD; surface soil moisture, SMsurf; and root-zone soil moisture, SMroot), and atmospheric CO2 to the changes of PWS indicated by ESILAI over the past four decades with a Random Forest model. ESILAI is the evaporative stress index that accounts for dynamical changes in Leaf Arae Index (LAI). a. Spatial distribution of dominant factor; b. Area ratio for the distribution of each dominant factor in a. Credit: Chang et al. [2026], Figure 7

Citation: Chang, Q., Wang, L., Barnes, M. L., Ficklin, D. L., Benson, M. C., & Novick, K. A. (2026). Widespread increase in global plant water stress obscured by greening. AGU Advances, 7, e2025AV002243. https://doi.org/10.1029/2025AV002243

—Ana P. Barros, Editor, AGU Advances

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