Rising ecosystem water demand exacerbates the lengthening of tropical dry seasons

Hao Xu; Xu Lian; Ingrid J Slette; Hui Yang; Yuan Zhang; Anping Chen; Shilong Piao

doi:10.1038/s41467-022-31826-y

Rising ecosystem water demand exacerbates the lengthening of tropical dry seasons

Nat Commun. 2022 Jul 14;13(1):4093. doi: 10.1038/s41467-022-31826-y.

Authors

Hao Xu¹, Xu Lian^{1

2}, Ingrid J Slette^{3

4

5}, Hui Yang⁶, Yuan Zhang⁷, Anping Chen^{3

4}, Shilong Piao^{8

9}

Affiliations

¹ Sino-French Institute for Earth System Science, College of Urban and Environmental Sciences, Peking University, Beijing, 100871, China.
² Department of Earth and Environmental Engineering, Columbia University, New York, NY, 10027, USA.
³ Department of Biology, Colorado State University, Fort Collins, CO, 80523, USA.
⁴ Graduate Degree Program in Ecology, Colorado State University, Fort Collins, CO, 80523, USA.
⁵ Long Term Ecological Research Network Office, National Center for Ecological Analysis and Synthesis, University of California Santa Barbara, Santa Barbara, CA, 93101, USA.
⁶ Department of Biogeochemical Integration, Max Planck Institute for Biogeochemistry, 07745, Jena, Germany.
⁷ Laboratoire des Sciences du Climat et de l'Environnement, CEA CNRS UVSQ, Gif-sur-Yvette, 91191, France.
⁸ Sino-French Institute for Earth System Science, College of Urban and Environmental Sciences, Peking University, Beijing, 100871, China. slpiao@pku.edu.cn.
⁹ State Key Laboratory of Tibetan Plateau Earth System, Resources and Environment, Institute of Tibetan Plateau Research, Chinese Academy of Sciences, Beijing, 100085, China. slpiao@pku.edu.cn.

Abstract

Precipitation-based assessments show a lengthening of tropical dry seasons under climate change, without considering simultaneous changes in ecosystem water demand. Here, we compare changes in tropical dry season length and timing when dry season is defined as the period when precipitation is less than: its climatological average, potential evapotranspiration, or actual evapotranspiration. While all definitions show more widespread tropical drying than wetting for 1983-2016, we find the largest fraction (48.7%) of tropical land probably experiencing longer dry seasons when dry season is defined as the period when precipitation cannot meet the need of actual evapotranspiration. Southern Amazonia (due to delayed end) and central Africa (due to earlier onset and delayed end) are hotspots of dry season lengthening, with greater certainty when accounting for water demand changes. Therefore, it is necessary to account for changing water demand when characterizing changes in tropical dry periods and ecosystem water deficits.

Publication types

Research Support, Non-U.S. Gov't
Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

Climate Change
Ecosystem*
Rain
Seasons
Tropical Climate
Water*

Substances

Water