Little change in global drought over the past 60 years
Abstract
Drought is expected to increase in frequency and severity in the future as a result of climate change, mainly as a consequence of decreases in regional precipitation but also because of increasing evaporation driven by global warming. Previous assessments of historic changes in drought over the late twentieth and early twenty-first centuries indicate that this may already be happening globally. In particular, calculations of the Palmer Drought Severity Index (PDSI) show a decrease in moisture globally since the 1970s with a commensurate increase in the area in drought that is attributed, in part, to global warming. The simplicity of the PDSI, which is calculated from a simple water-balance model forced by monthly precipitation and temperature data, makes it an attractive tool in large-scale drought assessments, but may give biased results in the context of climate change. Here we show that the previously reported increase in global drought is overestimated because the PDSI uses a simplified model of potential evaporation that responds only to changes in temperature and thus responds incorrectly to global warming in recent decades. More realistic calculations, based on the underlying physical principles that take into account changes in available energy, humidity and wind speed, suggest that there has been little change in drought over the past 60 years. The results have implications for how we interpret the impact of global warming on the hydrological cycle and its extremes, and may help to explain why palaeoclimate drought reconstructions based on tree-ring data diverge from the PDSI-based drought record in recent years.
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Two recent studies published in Nature Climate Change and Nature reached opposing conclusions about whether there are noticeable changes in drought trends due to climate change.
“Two recent studies published in Nature Climate Change 25 and Nature 26 came to opposing conclusions about whether there are noticeable changes in drought trends as a result of climate change.”
From A Big Data Guide to Understanding Climate Change: The Case for Theory-Guided Data Science (2014) · cites this paper as [26]
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“Soil water deficits during drought impose a reduction in stomatal conductance, thereby reducing evaporative cooling and thus increasing near-surface temperatures (14).”
BackgroundRecent global decline in endorheic basin water storages
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A new global database of meteorological drought events from 1951 to 2016
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Self-citationRapid warming accelerates tree growth decline in semi‐arid forests of Inner Asia
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“We repeated these correlation analyses for potential evaporation (which is dictated by VPD, wind speed, and radiation) using Sheffield et al. (2012) estimates of monthly potential evaporation (PET).”
BackgroundMethodChen, H., & Sun, J. (2015) · Journal of Climate · doi:10.1175/jcli-d-14-00707.1 · Cited by 417 · see citing works
“Furthermore, a few recent studies have claimed that the drought indices provide better estimates of the true global drought trend when using the PM evapotranspiration framework because of its more comprehensive physics (Sheffield et al. 2012; Trenberth et al. 2014).”
Future heat-waves, droughts and floods in 571 European cities
Guerreiro, S. B., Dawson, R., Kilsby, C. G., Lewis, E., & Ford, A. (2018) · Environmental Research Letters · doi:10.1088/1748-9326/aaaad3 · Cited by 417 · see citing works
“Observed changes in droughts are method-dependent (Sheffield et al 2012, Dai 2013, Trenberth et al 2014) while changes in precipitation extremes are spatiallyheterogeneous (Donat et al 2013).”
MethodSelf-amplified Amazon forest loss due to vegetation-atmosphere feedbacks
Zemp, D. C., Schleussner, C.-F., Barbosa, H. M. J., Hirota, M., Montade, V., Sampaio, G., Staal, A., Wang-Erlandsson, L., & Rammig, A. (2017) · Nature Communications · doi:10.1038/ncomms14681 · Cited by 413 · see citing works
Projected Impacts of Climate Change on Drought Patterns Over East Africa
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The biggest drought events in Europe from 1950 to 2012
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Human water consumption intensifies hydrological drought worldwide
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“Recent studies by Dai (2011, 2013) and Sheffield et al (2012) suggest that anthropogenic global warming is likely responsible for intensifying meteorological droughts, e.g. enhanced evaporative demand and altered monsoon circulation over regions such as Africa and Asia.”
BackgroundAnthropogenic Drought: Definition, Challenges, and Opportunities
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Climate Change and Drought: the Soil Moisture Perspective
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Self-citationRETRACTED ARTICLE: Warming accelerates global drought severity
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“Sheffield et al. (2012) analyzed, at the global 49 scale, the influence of using a simple empirical temperature-based formulation and a more physical 50 model, based on several meteorological variables, to estimate ETo.”
BackgroundMethodInfluentialBenchmark products for land evapotranspiration: LandFlux-EVAL multi-data set synthesis
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“Furthermore, it has been suggested that climate change may exacerbate the present shortage of water and is likely to increase drought in some Earth regions (IPCC 2007), although this has not happened yet at the extent predicted (Dai 2011; Sheffield et al. 2012).”
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Changes in concurrent monthly precipitation and temperature extremes
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“These data are interpolated to a 0.5◦ × 0.5◦ resolution and have been used in a variety of studies (Rawlins et al 2012, Sheffield et al 2012).”
MethodInfluentialA review of remote sensing applications for water security: Quantity, quality, and extremes
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“Recent studies (Dai, 2013; Sheffield et al., 2012) on observed global drought changes over the 20th century also find contradictory results, depending on the investigated indices.”
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A two-fold increase of carbon cycle sensitivity to tropical temperature variations
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“…at global or continental scales for present and future climate (e.g., Andreadis et al., 2005; Sheffield and Wood, 2008a, b; Shukla and Wood, 2008; Sheffield et al., 2009, 2012; Dai, 2011, 2013; Hannaford et al., 2010; Prudhomme et al., 2011; Stahl et al., 2011; Corzo Perez et al., 2011; Wehner…”
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“Climate change is expected to cause more frequent and severe drought in large areas of the planet (Sheffield et al., 2012).”
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“, 2016), and global to regional assessments of the recurrence of extreme hydrological droughts and their impact on ecosystems (Sheffield and Wood, 2007; Sheffield et al., 2012; Beguería et al., 2014; Griffin and Anchukaitis, 2014; Kusche et al., 2016; Dai and Zhao, 2016; Spinoni et al., 2017; Heim, 2017; Rudd et al.,…”
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“Previous studies have argued that the Penman-Monteith model yields more physically accurate predictions of potential evapotranspiration than models that only include temperature and radiation [Sheffield et al., 2012].”
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- Authors
- Sheffield, J., Wood, E. F., & Roderick, M. L.
- Affiliations
- Princeton University (US)
- Australian National University (AU)
- Corresponding author
- Sheffield, Justin
- Venue
- Nature
- Published
- 2012-11
- Volume
- 491
- Issue
- 7424
- Pages
- 435-438
- ISSN
- 0028-0836 (ISSN-L)
- 1476-4687
- OpenAlex
- W2015522309
- Cited by
- 1,978
- References
- 50
- Citations by year
- 2026: 97 · 2025: 126 · 2024: 131 · 2023: 162 · 2022: 188 · 2021: 196 · 2020: 174 · 2019: 159 · 2018: 160 · 2017: 139 · 2016: 144 · 2015: 121 · 2014: 110 · 2013: 66 · 2012: 3
- FWCI
- 79.51
- Type
- journal article
- Language
- en
- Open access
- closed
- Locations
- Nature (publishedVersion)
- PubMed (publishedVersion)
- RePEc: Research Papers in Economics (submittedVersion)
- ePrints Soton (University of Southampton) (submittedVersion)
- ANU Open Research (Australian National University) (submittedVersion)
- Topics
- Physical Sciences › Environmental Science › Global and Planetary Change › Hydrology and Drought Analysis
- Physical Sciences › Environmental Science › Global and Planetary Change › Plant Water Relations and Carbon Dynamics
- Physical Sciences › Environmental Science › Global and Planetary Change › Climate variability and models
- Keywords
- global drought, Palmer Drought Severity Index, drought trends, potential evaporation, global warming, water cycle, drought indices, climate change impacts, water balance modeling
- MeSH terms
- Models, Theoretical, Temperature, Time Factors, Droughts, Global Warming
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