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.

  • Letter
  • Published:

Reductions in labour capacity from heat stress under climate warming


A fundamental aspect of greenhouse-gas-induced warming is a global-scale increase in absolute humidity1,2. Under continued warming, this response has been shown to pose increasingly severe limitations on human activity in tropical and mid-latitudes during peak months of heat stress3. One heat-stress metric with broad occupational health applications4,5,6 is wet-bulb globe temperature. We combine wet-bulb globe temperatures from global climate historical reanalysis7 and Earth System Model (ESM2M) projections8,9,10 with industrial4 and military5 guidelines for an acclimated individual’s occupational capacity to safely perform sustained labour under environmental heat stress (labour capacity)—here defined as a global population-weighted metric temporally fixed at the 2010 distribution. We estimate that environmental heat stress has reduced labour capacity to 90% in peak months over the past few decades. ESM2M projects labour capacity reduction to 80% in peak months by 2050. Under the highest scenario considered (Representative Concentration Pathway 8.5), ESM2M projects labour capacity reduction to less than 40% by 2200 in peak months, with most tropical and mid-latitudes experiencing extreme climatological heat stress. Uncertainties and caveats associated with these projections include climate sensitivity, climate warming patterns, CO2 emissions, future population distributions, and technological and societal change.

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

Access options

Buy this article

Prices may be subject to local taxes which are calculated during checkout

Figure 1: Ten-year maximum monthly mean WBGT from WBT and 2 m reference temperature (Tref) as a proxy for globe temperature (WBGT = 0.7×WBT+0.3×Tref; °C) from ESM2M Tref, 2 m reference relative humidity, and surface pressure after mean and variance bias correction to reanalysis.
Figure 2: Population-weighted individual labour capacity (%) during annual mimimum (upper lines) and maximum (lower lines) heat stress months.

Similar content being viewed by others


  1. Manabe, S. & Wetherald, R. T. The effects of doubling CO2 concentration on the climate of a general circulation model. J. Atmos. Sci. 32, 3–15 (1975).

    Article  CAS  Google Scholar 

  2. Manabe, S. & Stouffer, R. J. A CO2-climate sensitivity study with a mathematical model of the global climate. Nature 282, 491–493 (1979).

    Article  CAS  Google Scholar 

  3. Delworth, T. L., Mahlman, J. D. & Knutson, T. R. Changes in heat index associated with CO2-induced global warming. Climatic Change 43, 369–386 (1999).

    Article  CAS  Google Scholar 

  4. American Conference of Governmental Industrial Hygienists Threshold Limit Values for Chemical Substances and Physical Agents. Biological Exposure Indices (ACGIH, 1996).

  5. Heat Stress Control and Heat Casualty Management Technical Bulletin Medical 507/Air Force Pamphlet 48-152 (US Army, 2003).

  6. Parsons, K. Heat stress standard ISO 7243 and its global application. Ind. Health 44, 368–379 (2006).

    Article  Google Scholar 

  7. Kalnay, E. et al. The NCEP/NCAR 40-Year Reanalysis Project. BAMS 77, 437–470 (1996).

    Article  Google Scholar 

  8. Dunne, J. P. et al. GFDL’s ESM2 global coupled climate-carbon Earth System Models Part I: Physical formulation and baseline simulation characteristics. J. Clim. 25, 6646–6665 (2012).

    Article  Google Scholar 

  9. Moss, R. H. et al. The next generation of scenarios for climate change research and assessment. Nature 463, 747–756 (2010).

    Article  CAS  Google Scholar 

  10. Meinshausen, M. et al. The RCP greenhouse gas concentrations and their extensions from 1765 to 2300. Climatic Change 109, 213–241 (2011).

    Article  CAS  Google Scholar 

  11. Cubasch, U. et al. in IPCC Climate Change 2001: The Scientific Basis (eds Houghton, J. T. et al.) 525–582 (Cambridge Univ. Press, 2001).

    Google Scholar 

  12. Confalonieri, U. et al. in IPCC Climate Change 2007: Impacts, Adaptation and Vulnerability (eds Parry, M. L. et al.) 391–431 (Cambridge Univ. Press, 2007).

    Google Scholar 

  13. Steadman, R. G. The assessment of sultriness. Part I: A temperature–humidity index based on human physiology and clothing science. J. Appl. Meteorol. 18, 861–873 (1979).

    Article  Google Scholar 

  14. Willett, K. M. & Sherwood, S. C. Exceedance of heat index thresholds for 15 regions under a warming climate using the wet-bulb globe temperature. Int. J. Climatol. 32, 161–177 (2012).

    Article  Google Scholar 

  15. Jendritzky, G. & Tinz, B. The thermal environment of the human being on the global scale. Glob. Health Action 2 (Special volume), 10–21 (2009).

    Google Scholar 

  16. Sherwood, S. C. & Huber, M. An adaptability limit to climate change due to heat stress. Proc. Natl Acad. Sci. USA 107, 9552–9555 (2010).

    Article  CAS  Google Scholar 

  17. Kjellstrom, T., Holmer, I. & Lemke, B. Workplace heat stress, health and productivity—an increasing challenge for low and middle-income countries during climate change. Glob. Health Action 2 (Special volume), 46–51 (2009).

    Google Scholar 

  18. Epstein, Y. & Moran, D. S. Thermal comfort and the heat stress indices. Ind. Health 44, 388–398 (2006).

    Article  Google Scholar 

  19. Davies-Jones, R. An efficient and accurate method for computing the wet-bulb temperature along pseudoadiabats. Mon. Weath. Rev. 136, 2764–2785 (2008).

    Article  Google Scholar 

  20. Taylor, K. E., Stouffer, R. J. & Meehl, G. A. An overview of CMIP5 and the experiment design. BAMS 93, 485–498 (2012).

    Article  Google Scholar 

  21. Delworth, T. L. et al. GFDL’s CM2 global coupled climate models. Part I: Formulation and simulation characteristics. J. Clim. 19, 643–674 (2006).

    Article  Google Scholar 

  22. Winton, M. et al. Influence of ocean and atmosphere components on simulated climate sensitivities. J. Clim. 26, 231–245 (2013).

    Article  Google Scholar 

  23. Meehl, G. A. et al. in IPCC Climate Change 2007: The Physical Science Basis (eds S., Solomon et al.) 747–845 (Cambridge Univ. Press, 2007).

    Google Scholar 

  24. Reichler, T. & Kim, J. How well do coupled models simulate today’s climate? BAMS 89, 303–311 (2008).

    Article  Google Scholar 

  25. Guilyardi, E. et al. Understanding El Niño in ocean–atmosphere general circulation models. BAMS 90, 325–340 (2009).

    Article  Google Scholar 

  26. Hegerl, G. C. et al. in IPCC Climate Change 2007: The Physical Science Basis (eds Solomon, S. et al.) 663–745 (Cambridge Univ. Press, 2007).

    Google Scholar 

  27. Meinshausen, M. et al. Greenhouse-gas emission targets for limiting global warming to 2 °C. Nature 458, 1158–1162 (2009).

    Article  CAS  Google Scholar 

  28. McCarthy, M. P., Best, M. J. & Betts, R. A. Climate change in cities due to global warming and urban effects. Geophys. Res. Lett. 37, L09705 (2010).

    Article  Google Scholar 

  29. Fischer, E. M., Oleson, K. W. & Lawrence, D. M. Contrasting urban and rural heat stress responses to climate change. Geophys. Res. Lett. 39, L03705 (2012).

    Google Scholar 

  30. Rogner, H-H. et al. Global Energy Assessment—Toward a Sustainable Future 425–512 (Cambridge Univ. Press and IIASA, 2012).

    Book  Google Scholar 

  31. Schindler, J. & Wittel, Z. Crude Oil: The Supply Outlook Report to the Energy Watch Group EWG Series No 3/2007 (Energy Watch Group, 2007).

  32. Rutledge, D. Estimating long-term world coal production with logit and probit transforms. Int. J. Coal Geol. 85, 23–33 (2011).

    Article  CAS  Google Scholar 

  33. Christensen, J. H. et al. in IPCC Climate Change 2001: The Scientific Basis (eds Houghton, J. T. et al.) 847–865 (Cambridge Univ. Press, 2001).

    Google Scholar 

  34. Fischer, E. M. & Knutti, R. Robust projections of combined humidity and temperature extremes. Nature Clim. Change 3, 126–130 (2013).

    Article  Google Scholar 

  35. Bolton, D. The computation of equivalent potential temperature. Mon. Weath. Rev. 108, 1046–1053 (1980).

    Article  Google Scholar 

  36. Wexler, A. Vapor pressure formulation for water in range 0 to 100C. A revision. J. Res. Nat. Bur. Stand. 80A, 775–785 (1976).

    Article  CAS  Google Scholar 

Download references


The scientific results and conclusions, as well as any views or opinions expressed herein, are those of the authors and do not necessarily reflect the views of NOAA or the US Department of Commerce. The authors thank I. Held, T. Delworth, T. Knutson and V. Ramaswamy for constructive criticisms to improve the manuscript.

Author information

Authors and Affiliations



J.P.D. designed the study, conducted the analysis and wrote the manuscript. J.G.J. performed experiments and gave technical advice. R.J.S. provided technical and conceptual advice.

Corresponding author

Correspondence to John P. Dunne.

Ethics declarations

Competing interests

The authors declare no competing financial interests.

Supplementary information

Supplementary Information

Supplementary Information (PDF 1331 kb)

Rights and permissions

Reprints and permissions

About this article

Cite this article

Dunne, J., Stouffer, R. & John, J. Reductions in labour capacity from heat stress under climate warming. Nature Clim Change 3, 563–566 (2013).

Download citation

  • Received:

  • Accepted:

  • Published:

  • Issue Date:

  • DOI:


Quick links

Nature Briefing Anthropocene

Sign up for the Nature Briefing: Anthropocene newsletter — what matters in anthropocene research, free to your inbox weekly.

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