Warming Climate Amplifies Vapor Pressure Deficit Limits on Gross Primary Productivity

Authors

• Shiqin Xu, King Abdullah University of Science and Technology
• Nate G. McDowell, Pacific Northwest National Lab
• Tim R. McVicar, CSIRO Environment
• Diego G. Miralles, Ghent University
• Stephen Sitch, University of Exeter
• Pablo Sanchez-Martinez, University of Exeter
• Joshua B. Fisher, Chapman UniversityFollow
• Pierre Friedlingstein, University of Exeter
• Hylke E. Beck, King Abdullah University of Science and Technology
• Matthew F. McCabe, King Abdullah University of Science and Technology

Document Type

Article

Publication Date

4-30-2026

Abstract

Ongoing climate warming may profoundly impact terrestrial gross primary productivity (GPP), a key component of the global carbon cycle. However, uncertainty in the relative roles of atmospheric water demand (vapor pressure deficit, VPD) and root-zone soil moisture (SM) limits predictions of drought impacts on GPP. Here, we show that growing-season GPP was more strongly constrained by VPD than SM globally, based on observation-constrained model estimates, satellite retrievals and Dynamic Global Vegetation Model simulations. The importance of VPD increased with higher temperatures and more severe and prolonged droughts. This pattern reflects VPD’s critical role in regulating stomatal conductance and plant hydraulic function, both of which are essential for preventing xylem embolism. We further found that P₅₀, the water potential at 50% loss of hydraulic conductivity, was the strongest predictor of their relative influence. Collectively, rising VPD may accelerate declines in terrestrial carbon storage under future warming.

Comments

This article was originally published in Nature Communications, volume 17, in 2026. https://doi.org/10.1038/s41467-026-72549-8

Recommended Citation

Xu, S., McDowell, N.G., McVicar, T.R. et al. Warming climate amplifies vapor pressure deficit limits on gross primary productivity. Nat Commun 17, 6149 (2026). https://doi.org/10.1038/s41467-026-72549-8

Copyright

The authors

Creative Commons License

This work is licensed under a Creative Commons Attribution-Noncommercial-No Derivative Works 4.0 License.