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Advances in understanding large‐scale responses of the water cycle to climate change
Author(s) -
Allan Richard P.,
Barlow Mathew,
Byrne Michael P.,
Cherchi Annalisa,
Douville Hervé,
Fowler Hayley J.,
Gan Thian Y.,
Pendergrass Angeline G.,
Rosenfeld Daniel,
Swann Abigail L. S.,
Wilcox Laura J.,
Zolina Olga
Publication year - 2020
Publication title -
annals of the new york academy of sciences
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.712
H-Index - 248
eISSN - 1749-6632
pISSN - 0077-8923
DOI - 10.1111/nyas.14337
Subject(s) - environmental science , water cycle , atmospheric sciences , precipitation , radiative forcing , climatology , climate model , climate change , greenhouse gas , forcing (mathematics) , aerosol , water balance , meteorology , ecology , physics , geotechnical engineering , engineering , biology , geology
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.