Skip to main content

Thank you for visiting You are using a browser version with limited support for CSS. To obtain the best experience, we recommend you use a more up to date browser (or turn off compatibility mode in Internet Explorer). In the meantime, to ensure continued support, we are displaying the site without styles and JavaScript.

Little change in global drought over the past 60 years


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 warming1,2,3. 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 warming4,5. 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 change6. Here we show that the previously reported increase in global drought is overestimated because the PDSI uses a simplified model of potential evaporation7 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 principles8 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 years9,10.

This is a preview of subscription content, access via your institution

Relevant articles

Open Access articles citing this article.

Access options

Buy article

Get time limited or full article access on ReadCube.


All prices are NET prices.

Figure 1: Global average time series of the PDSI and area in drought.
Figure 2: Trends in the PDSI and PE.


  1. Sheffield, J. & Wood, E. F. Projected changes in drought occurrence under future global warming from multi-model, multi-scenario, IPCC AR4 simulations. Clim. Dyn. 13, 79–105 (2008)

    Google Scholar 

  2. Dai, A. Drought under global warming: a review. Wiley Interdisc. Rev. Clim. Change 2, 45–65 (2010)

    Google Scholar 

  3. Seneviratne, S. I. et al. in Managing the Risks of Extreme Events and Disasters to Advance Climate Change Adaptation (eds Field, C. B. et al.) 109–230 (Intergovernmental Panel on Climate Change, 2012)

  4. Dai, A., Trenberth, K. E. & Qian, T. A global data set of Palmer Drought Severity Index for 1870–2002: relationship with soil moisture and effects of surface warming. J. Hydrometeorol. 5, 1117–1130 (2004)

    ADS  Google Scholar 

  5. Briffa, K. R. van der Schrier, G. & Jones, P. D. Wet and dry summers in Europe since 1750: evidence of increasing drought. Int. J. Climatol. 29, 1894–1905 (2009)

    Google Scholar 

  6. Roderick, M. L., Hobbins, M. T. & Farquhar, G. D. Pan evaporation trends and the terrestrial water balance II. Energy balance and interpretation. Geog. Compass 3, 761–780 (2009)

    Google Scholar 

  7. Thornthwaite, C. W. An approach toward a rational classification of climate. Geogr. Rev. 38, 55–94 (1948)

    Google Scholar 

  8. Penman, H. L. Natural evaporation from open water, bare soil, and grass. Proc. R. Soc. Lond. A 193, 120–145 (1948)

    ADS  CAS  Google Scholar 

  9. Fang, K. Y. et al. Drought variations in the eastern part of northwest China over the past two centuries: evidence from tree rings. Clim. Res. 38, 129–135 (2009)

    Google Scholar 

  10. de Grandpré, L. et al. Seasonal shift in the climate responses of Pinus sibirica, Pinus sylvestris, and Larix sibirica trees from semi-arid, north-central Mongolia. Can. J. For. Res. 41, 1242–1255 (2011)

    Google Scholar 

  11. Sternberg, T. Regional drought has a global impact. Nature 472, 169 (2011)

    CAS  PubMed  Google Scholar 

  12. Cai, W., Cowan, T., Briggs, P. & Raupach, M. Rising temperature depletes soil moisture and exacerbates severe drought conditions across southeast Australia. Geophys. Res. Lett. 36, L21709 (2009)

    ADS  Google Scholar 

  13. IPCC. Climate Change 2007: The Physical Science Basis. Contribution of Working Group I to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change (eds Solomon, S. et al.) (Cambridge Univ. Press, 2007)

  14. Wang, J., Chen, F., Jin, L. & Bai, H. Characteristics of the dry/wet trend over arid central Asia over the past 100 years. Clim. Res. 41, 51–59 (2010)

    Google Scholar 

  15. Palmer, W. C. Meteorological Drought (US Department of Commerce Research Paper 45, 1965)

    Google Scholar 

  16. Zhao, M. & Running, S. W. Drought-induced reduction in global terrestrial net primary production from 2000 through 2009. Science 329, 940–943 (2010)

    ADS  CAS  PubMed  Google Scholar 

  17. Alley, W. M. The Palmer Drought Severity Index: limitations and assumptions. J. Clim. Appl. Meteorol. 23, 1100–1109 (1984)

    ADS  Google Scholar 

  18. Wells, N., Goddard, S. & Hayes, M. J. A self-calibrating Palmer drought severity index. J. Clim. 17, 2335–2351 (2004)

    ADS  Google Scholar 

  19. Shuttleworth, W. J. in Handbook of Hydrology (ed. Maidment, D. R. ) 4.1–4.53 (McGraw-Hill, 1993)

    Google Scholar 

  20. Roderick, M. L., Rotstayn, L. D., Farquhar, G. D. & Hobbins, M. T. On the attribution of changing pan evaporation. Geophys. Res. Lett. 34, L17403 (2007)

    ADS  Google Scholar 

  21. Donohue, R. J., McVicar, T. R. & Roderick, M. L. Assessing the ability of potential evaporation formulations to capture the dynamics in evaporative demand within a changing climate. J. Hydrol. (Amst.) 386, 186–197 (2010)

    ADS  Google Scholar 

  22. Shaw, S. & Riha, S. J. Assessing temperature-based PET equations under a changing climate in temperate, deciduous forests. Hydrol. Process. 25, 1466–1478 (2011)

    ADS  Google Scholar 

  23. Monteith, J. L. Evaporation and environment. Symp. Soc. Exp. Biol. 19, 205–234 (1964)

    Google Scholar 

  24. Dai, A. Characteristics and trends in various forms of the Palmer Drought Severity Index during 1900–2008. J. Geophys. Res. 116, D12115 (2011)

    ADS  Google Scholar 

  25. van der Schrier, G., Jones, P. D. & Briffa, K. R. The sensitivity of the PDSI to the Thornthwaite and Penman–Monteith parameterizations for potential evapotranspiration. J. Geophys. Res. 116, D03106 (2011)

    ADS  Google Scholar 

  26. D’Arrigo, R., Wilson, R., Liepert, B. & Cherubini, P. On the ‘Divergence Problem’ in northern forests: a review of the tree-ring evidence and possible causes. Global Planet. Change 60, 289–305 (2008)

    ADS  Google Scholar 

  27. Roderick, M. L. & Farquhar, G. D. Changes in Australian pan evaporation from 1970 to 2002. Int. J. Climatol. 24, 1077–1090 (2004)

    Google Scholar 

  28. Lockart, N., Kavetski, D. & Franks, S. W. On the recent warming in the Murray–Darling Basin: land surface interactions misunderstood. Geophys. Res. Lett. 36, L24405 (2009)

    ADS  Google Scholar 

  29. Hirschi, M. et al. Observational evidence for soil-moisture impact on hot extremes in southeastern Europe. Nature Geosci. 4, 17–21 (2011)

    ADS  CAS  Google Scholar 

  30. Milly, P. C. D. & Dunne, K. A. On the hydrologic adjustment of climate-model projections: the potential pitfall of potential evapotranspiration. Earth Interact. 15, 1–14 (2011)

    ADS  Google Scholar 

  31. Sheffield, J., Goteti, G. & Wood, E. F. Development of a 50-yr high-resolution global dataset of meteorological forcings for land surface modeling. J. Clim. 19, 3088–3111 (2006)

    ADS  Google Scholar 

  32. Svoboda, M. et al. The Drought Monitor. Bull. Am. Meteorol. Soc. 83, 1181–1190 (2002)

    ADS  Google Scholar 

  33. Cook, E. R., Meko, D. M., Stahle, D. W. & Cleaveland, M. K. Drought reconstructions for the continental United States. J. Clim. 12, 1145–1162 (1999)

    ADS  Google Scholar 

  34. van der Schrier, G., Briffa, K. R., Osborn, T. J. & Cook, E. R. Summer moisture availability across North America. J. Geophys. Res. 111, D11102 (2006)

    ADS  Google Scholar 

  35. McCabe, G. J. & Palecki, M. A. Multidecadal climate variability of global lands and oceans. Int. J. Climatol. 26, 849–865 (2006)

    Google Scholar 

  36. Sheffield, J. & Wood, E. F. Characteristics of global and regional drought, 1950–2000: analysis of soil moisture data from off-line simulation of the terrestrial hydrologic cycle. J. Geophys. Res. 112, D17115 (2007)

    ADS  Google Scholar 

  37. Jensen, M. E. Consumptive Use of Water and Irrigation Water Requirements (American Society of Civil Engineers, 1973)

    Google Scholar 

  38. Mu, Q. et al. Development of a global evapotranspiration algorithm based on MODIS and global meteorology data. J. Geophys. Res. 112, G01012 (2007)

    Google Scholar 

  39. Cleugh, H. A., Leuning, R., Mu, Q. & Running, S. W. Regional evaporation estimates from flux tower and MODIS satellite data. Remote Sens. Environ. 106, 285–304 (2007)

    ADS  Google Scholar 

  40. Sheffield, J., Wood, E. F. & Munoz-Arriola, F. Long-term regional estimates of evapotranspiration for Mexico based on downscaled ISCCP data. J. Hydrometeorol. 11, 253–275 (2010)

    ADS  Google Scholar 

  41. Kalnay, E. et al. The NCEP/NCAR 40-Year Reanalysis Project. Bull. Am. Meteorol. Soc. 77, 437–471 (1996)

    ADS  Google Scholar 

  42. Mitchell, T. D. & Jones, P. D. An improved method of constructing a database of monthly climate observations and associated high-resolution grids. Int. J. Climatol. 25, 693–712 (2005)

    Google Scholar 

  43. Huffman, G. J. et al. The TRMM Multisatellite Precipitation Analysis (TMPA): Quasi-global, multiyear, combined-sensor precipitation estimates at fine scales. J. Hydrometeorol. 8, 38–55 (2007)

    ADS  Google Scholar 

  44. Gupta, S. K., Stackhouse, P. W., Cox, S. J., Mikovitz, J. C. & Zhang, T. Surface Radiation Budget Project completes 22-year data set. GEWEX News 16, 12–13 (2006)

    Google Scholar 

  45. Chen, M., Xie, P., Janowiak, J. E. & Arkin, P. A. Global land precipitation: a 50-yr monthly analysis based on gauge observations. J. Hydrometeorol. 3, 249–266 (2002)

    ADS  Google Scholar 

  46. Schneider, U., Fuchs, T., Meyer-Christoffer, A. & Rudolf, B. Global precipitation analysis products of the GPCC. Weather and Climate—Deutscher Wetterdienst—Klimadatenzentrum-WZN <> (2008)

  47. Willmott, C. J. & Matsuura, K. Terrestrial Air Temperature: 1900–2008 Gridded Monthly Time Series, version 2.01. Global Air Temperature Archive <> (2010)

Download references


J.S. acknowledges support from the US National Oceanic and Atmospheric Agency (NA10OAR4310130, NA11OAR4310097) and NASA (NNX08AN40A). M.L.R. acknowledges the support of the Australian Research Council (DP0879763, DP110105376, CE11E0098).

Author information

Authors and Affiliations



J.S. and E.F.W. conceived the study with inspiration from M.L.R. J.S. performed the analyses and mainly wrote the manuscript. E.F.W. and M.L.R. contributed to discussion and the manuscript.

Corresponding author

Correspondence to Justin Sheffield.

Ethics declarations

Competing interests

The authors declare no competing financial interests.

Supplementary information

Supplementary Information

This file contains Supplementary Text, Supplementary Figures 1-19, Supplementary Table 1 and Supplementary References. (PDF 3400 kb)

PowerPoint slides

Rights and permissions

Reprints and Permissions

About this article

Cite this article

Sheffield, J., Wood, E. & Roderick, M. Little change in global drought over the past 60 years. Nature 491, 435–438 (2012).

Download citation

  • Received:

  • Accepted:

  • Published:

  • Issue Date:

  • DOI:

Further reading


By submitting a comment you agree to abide by our Terms and Community Guidelines. If you find something abusive or that does not comply with our terms or guidelines please flag it as inappropriate.


Quick links

Nature Briefing

Sign up for the Nature Briefing newsletter — what matters in science, free to your inbox daily.

Get the most important science stories of the day, free in your inbox. Sign up for Nature Briefing