Soil moisture–atmosphere feedbacks mitigate declining water availability in drylands

Sha Zhou, A. Park Williams, Benjamin R. Lintner, Alexis M. Berg, Yao Zhang, Trevor F. Keenan, Benjamin I. Cook, Stefan Hagemann, Sonia I. Seneviratne, Pierre Gentine

Research output: Contribution to journalArticlepeer-review

1 Scopus citations

Abstract

Global warming alters surface water availability (precipitation minus evapotranspiration, P–E) and hence freshwater resources. However, the influence of land–atmosphere feedbacks on future P–E changes and the underlying mechanisms remain unclear. Here we demonstrate that soil moisture (SM) strongly impacts future P–E changes, especially in drylands, by regulating evapotranspiration and atmospheric moisture inflow. Using modelling and empirical approaches, we find a consistent negative SM feedback on P–E, which may offset ~60% of the decline in dryland P–E otherwise expected in the absence of SM feedbacks. The negative feedback is not caused by atmospheric thermodynamic responses to declining SM; rather, reduced SM, in addition to limiting evapotranspiration, regulates atmospheric circulation and vertical ascent to enhance moisture transport into drylands. This SM effect is a large source of uncertainty in projected dryland P–E changes, underscoring the need to better constrain future SM changes and improve the representation of SM–atmosphere processes in models.

Original languageEnglish (US)
Pages (from-to)38-44
Number of pages7
JournalNature Climate Change
Volume11
Issue number1
DOIs
StatePublished - Jan 2021

All Science Journal Classification (ASJC) codes

  • Environmental Science (miscellaneous)
  • Social Sciences (miscellaneous)

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