Advances in understanding large-scale responses of the water cycle to climate change

Richard P. Allan, Mathew Barlow, Michael P. Byrne, Annalisa Cherchi, Hervé Douville, Hayley J. Fowler, Thian Y. Gan, Angeline G. Pendergrass, Daniel Rosenfeld, Abigail L. S. Swann, Laura J. Wilcox, Olga Zolina

Research output: Contribution to journalReview articlepeer-review

29 Citations (Scopus)

Abstract

Globally, thermodynamics explains an increase in atmospheric water vapor with warming of around 7%/°C near to the surface. In contrast, global precipitation and evaporation are constrained by the Earth's energy balance to increase at ∼2–3%/°C. However, this rate of increase is suppressed by rapid atmospheric adjustments in response to greenhouse gases and absorbing aerosols that directly alter the atmospheric energy budget. Rapid adjustments to forcings, cooling effects from scattering aerosol, and observational uncertainty can explain why observed global precipitation responses are currently difficult to detect but are expected to emerge and accelerate as warming increases and aerosol forcing diminishes. Precipitation increases with warming are expected to be smaller over land than ocean due to limitations on moisture convergence, exacerbated by feedbacks and affected by rapid adjustments. Thermodynamic increases in atmospheric moisture fluxes amplify wet and dry events, driving an intensification of precipitation extremes. The rate of intensification can deviate from a simple thermodynamic response due to in‐storm and larger‐scale feedback processes, while changes in large‐scale dynamics and catchment characteristics further modulate the frequency of flooding in response to precipitation increases. Changes in atmospheric circulation in response to radiative forcing and evolving surface temperature patterns are capable of dominating water cycle changes in some regions. Moreover, the direct impact of human activities on the water cycle through water abstraction, irrigation, and land use change is already a significant component of regional water cycle change and is expected to further increase in importance as water demand grows with global population.
Original languageEnglish
Number of pages27
JournalAnnals of the New York Academy of Sciences
VolumeEarly View
Early online date4 Apr 2020
DOIs
Publication statusE-pub ahead of print - 4 Apr 2020

Keywords

  • Climate change
  • Water cycle
  • Precipitation
  • Land surface
  • Radiative forcing

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