Validity of estimating flood and drought characteristics under equilibrium climates from transient simulations

Julien Boulange*, Naota Hanasaki, Yusuke Satoh, Tokuta Yokohata, Hideo Shiogama, Peter Burek, Wim Thiery, Dieter Gerten, Hannes Müller Schmied, Yoshihide Wada, Simon N. Gosling, Yadu Pokhrel, Niko Wanders

*Corresponding author for this work

Research output: Contribution to journalArticleAcademicpeer-review

Abstract

Future flood and drought risks have been predicted to transition from moderate to high levels at global warmings of 1.5 C and 2.0 C above pre-industrial levels, respectively. However, these results were obtained by approximating the equilibrium climate using transient simulations with steadily warming. This approach was recently criticised due to the warmer global land temperature and higher mean precipitation intensities of the transient climate in comparison with the equilibrium climate. Therefore, it is unclear whether floods and droughts projected under a transient climate can be systematically substituted for those occurring in an equilibrated climate. Here, by employing a large ensemble of global hydrological models (HMs) forced by global climate models, we assess the validity of estimating flood and drought characteristics under equilibrium climates from transient simulations. Differences in flood characteristics under transient and equilibrium climates could be largely ascribed to natural variability, indicating that the floods derived from a transient climate reasonably approximate the floods expected in an equally warm, equilibrated climate. By contrast, significant differences in drought intensity between transient and equilibrium climates were detected over a larger global land area than expected from natural variability. Despite the large differences among HMs in representing the low streamflow regime, we found that the drought intensities occurring under a transient climate may not validly represent the intensities in an equally warm equilibrated climate for approximately 6.7% of the global land area.

Original languageEnglish
Article number104028
Pages (from-to)1-10
JournalEnvironmental Research Letters
Volume16
Issue number10
DOIs
Publication statusPublished - Oct 2021

Bibliographical note

Funding Information:
Original content from this work may be used under the terms of the . Any further distribution of this work must maintain attribution to the author(s) and the title of the work, journal citation and DOI. Environment Research and Technology Development Fund JPMEERF20182R02 Ministry of Education, Culture, Sports and Technology/Japan Society for the Promotion of Science KAKENHI grant number 16H06291 National Science Foundation 1752729 yes � 2021 The Author(s). Published by IOP Publishing Ltd Creative Commons Attribution 4.0 license

Publisher Copyright:
© 2021 The Author(s). Published by IOP Publishing Ltd.

Funding

Original content from this work may be used under the terms of the . Any further distribution of this work must maintain attribution to the author(s) and the title of the work, journal citation and DOI. Environment Research and Technology Development Fund JPMEERF20182R02 Ministry of Education, Culture, Sports and Technology/Japan Society for the Promotion of Science KAKENHI grant number 16H06291 National Science Foundation 1752729 yes � 2021 The Author(s). Published by IOP Publishing Ltd Creative Commons Attribution 4.0 license

Keywords

  • climate change
  • droughts
  • equilibrium climate
  • floods
  • transient climate

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