Advances in understanding large-scale responses of the water cycle to climate change
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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.
Allan , R P , Barlow , M , Byrne , M P , Cherchi , A , Douville , H , Fowler , H J , Gan , T Y , Pendergrass , A G , Rosenfeld , D , Swann , A L S , Wilcox , L J & Zolina , O 2020 , ' Advances in understanding large-scale responses of the water cycle to climate change ' , Annals of the New York Academy of Sciences , vol. Early View . https://doi.org/10.1111/nyas.14337
Annals of the New York Academy of Sciences
Copyright © 2020 The Authors. Annals of the New York Academy of Sciences published by Wiley Periodicals, Inc. on behalf of New York Academy of Sciences. This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.
DescriptionR.P.A. is funded by the National Centre for Earth Observation and U.K. Natural Environment Research Council SMURPHS Grant (NE/N006054/1). H.J.F. is funded by the Wolfson Foundation and the Royal Society as a Royal Society Wolfson Research Merit Award holder (Grant WM140025). A.G.P. was supported by the Regional and Global Model Analysis (RGMA) component of the Earth and Environmental System Modeling Program of the U.S. Department of Energy's Office of Biological & Environmental Research (BER) via National Science Foundation (NSF) IA 1844590 and the National Center for Atmospheric Research, which is a major facility sponsored by the NSF under Cooperative Agreement No. 1947282.
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