Hydrological droughts in the 21st century, hotspots and uncertainties from a global multimodel ensemble experiment

By Christel Prudhomme, I. Giuntoli, E. Robinson, D. Clark, N. Arnell, R. Dankers, Balazs M. Fekete, W. Franssen, Dieter Gerten, Simon N. Gosling and 8 more. Proceedings of the National Academy of Sciences of the United States of America, 2013

728 citations recorded by the source corpus.

Significance Increasing concentrations of greenhouse gases in the atmosphere are widely expected to influence global climate over the coming century. The impact on drought is uncertain because of the complexity of the processes but can be estimated using outputs from an ensemble of global models (hydrological and climate models). Using an ensemble of 35 simulations, we show a likely increase in the global severity of drought by the end of 21st century, with regional hotspots including South America and Central and Western Europe in which the frequency of drought increases by more than 20%. The main source of uncertainty in the results comes from the hydrological models, with climate models contributing to a substantial but smaller amount of uncertainty. Increasing concentrations of greenhouse gases in the atmosphere are expected to modify the global water cycle with significant consequences for terrestrial hydrology. We assess the impact of climate change on hydrological droughts in a multimodel experiment including seven global impact models (GIMs) driven by bias-corrected climate from five global climate models under four representative concentration pathways (RCPs). Drought severity is defined as the fraction of land under drought conditions. Results show a likely increase in the global severity of hydrological drought at the end of the 21st century, with systematically greater increases for RCPs describing stronger radiative forcings. Under RCP8.5, droughts exceeding 40% of analyzed land area are projected by nearly half of the simulations. This increase in drought severity has a strong signal-to-noise ratio at the global scale, and Southern Europe, the Middle East, the Southeast United States, Chile, and South West Australia are identified as possible hotspots for future water security issues. The uncertainty due to GIMs is greater than that from global climate models, particularly if including a GIM that accounts for the dynamic response of plants to CO2 and climate, as this model simulates little or no increase in drought frequency. Our study demonstrates that different representations of terrestrial water-cycle processes in GIMs are responsible for a much larger uncertainty in the response of hydrological drought to climate change than previously thought. When assessing the impact of climate change on hydrology, it is therefore critical to consider a diverse range of GIMs to better capture the uncertainty.

Subfields: Global and Planetary Change, Water Science and Technology

View Paper: https://www.semanticscholar.org/paper/37604a35b4396af5f216ee7e6a1bb8c2cf17db58

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Citations in the corpus

High‐resolution modeling of human and climate impacts on global water resources (2016, background): “…(e.g., Asia, Africa), drought is closely associated with the presence of the El Ni~no-Southern Oscillation (ENSO) that has driven a number of severe drought events [Trenberth et al., 1988; Seager, 2007; Sheffield and Wood, 2007; Sheffield et al., 2012; Dankers et al., 2014; Prudhomme et al., 2014].”
Multimodel assessment of water scarcity under climate change (2013, background): “(40) in this issue of PNAS], affecting aquatic and terrestrial ecosystems (41), and potentially interacting with, and amplifying, climate change impacts in other sectors (42).”
The critical role of the routing scheme in simulating peak river discharge in global hydrological models (2017, methodology): “Hydrological modelling has been a useful tool to provide flood projections under various climate scenarios (Lehner et al 2006, Prudhomme et al 2014).”
Accelerating Poverty Reduction in Africa (2019, background): “L’Afrique de l’Est, qui subit actuellement un stress hydrique considérable, devrait connaître une amélioration de ses ressources en eau et une légère réduction du nombre de jours de sécheresse, tandis que le reste de l’Afrique enregistrera une augmentation de 10 à 20 % du nombre des jours de séchere”
Root Phenotyping for Drought Tolerance: A Review (2018, background): “Variation in climate alters the hydrologic cycle, and eventually reduces the availability of water due to a change in rainfall patterns, reduction in available water resources and reduction in water supply [9].”
Disaster risk, climate change, and poverty: assessing the global exposure of poor people to floods and droughts (2015, background): “, 2013, 2015) and drought risk (Prudhomme et al., 2014; Schewe et al., 2014) have led to improved estimates of the global population exposed to natural hazards under the current and future climate, but these have not been translated into results specific for different incomes within a country.”
Impacts of recent drought and warm years on water resources and electricity supply worldwide (2016, background): “Potential increases in the severity of streamflow droughts (e.g. Prudhomme et al 2014, Trenberth et al 2014) and heatwaves (e.g. Christidis et al 2015) under changing climate will therefore directly impact energy security.”
Worldwide evaluation of mean and extreme runoff from six global-scale hydrological models that account for human impacts (2018, background): “Global hydrological models (GHMs) and land surface models (LSMs) are used for assessing the impacts of climate change on water availability and scarcity [1– 5], droughts [6, 7], flood hazard and risk [8–11], the response of the global hydrological cycle to climate change mitigation [12], forecasting”