The authors thank Dr. Ramakrishna Nemani for his interest in this work and for sponsoring some of the computing resources used in model simulations performed on the NASA AMES computing system. The authors also thank Sean Davis for providing the reanalysis trend estimates based on DR12. The paper has benefited from the comments by Dr. Lorenzo Polvani on an earlier draft, and also from comments by an anonymous reviewer. We gratefully acknowledge NOAA’s Climate Program Office and NOAA’s Super-Computing System for support.
Allen, R. J., , S. C. Sherwood, , J. R. Norris, , and C. S. Zender, 2012: Recent Northern Hemisphere tropical expansion primarily driven by black carbon and tropospheric ozone. Nature, 485, 350–354.
Birner, T., 2010: Recent widening of the tropical belt from global tropopause statistics: Sensitivities. J. Geophys. Res., 115, D23109, doi:10.1029/2010JD014664.
Davis, S., , and K. Rosenlof, 2012: A multidiagnostic intercomparison of tropical-width time series using reanalyses and satellite observations. J. Climate, 25, 1061–1078.
Dee, D. P., and Coauthors, 2011: The ERA-Interim reanalysis: Configuration and performance of the data assimilation system. Quart. J. Roy. Meteor. Soc., 137, 553–597.
Deser, C., , and A. Phillips, 2009: Atmospheric circulation trends, 1950–2000: The relative role of sea surface temperature forcing and direct atmospheric forcing. J. Climate,22, 396–413.
Eyring, V., and Coauthors, 2013: Long-term ozone changes and associated climate impacts in CMIP5 simulations. J. Geophys. Res., 118, 5029–5060, doi:10.1002/jgrd.50316.
FAO, cited 2007: Coping with water scarcity. Food and Agricultural Organization. [Available online at http://www.fao.org/nr/water/docs/escarcity.pdf.]
Fu, Q., , and P. Lin, 2011: Poleward shift of subtropical jets inferred from satellite-observed lower stratospheric temperatures. J. Climate, 24, 5597–5603.
Held, I. M., , and B. J. Soden, 2006: Robust responses of the hydrological cycle to global warming. J. Climate,19, 5686–5699.
Hu, Y., , L. Tao, , and J. Liu, 2013: Poleward expansion of the Hadley circulation in CMIP5 simulations. Adv. Atmos. Sci., 30, 790–795.
Kang, S. M., , C. Deser, , and L. M. Polvani, 2013: Uncertainty in climate change projections of the Hadley circulation: The role of internal variability. J. Climate, 26, 7541–7554.
Lamarque, J.-F., and Coauthors, 2012: CAM-chem: Description and evaluation of interactive atmospheric chemistry in the Community Earth System Model. Geosci. Model Dev., 5, 369–411, doi:10.5194/gmd-5-369-2012.
Lu, J., , G. A. Vecchi, , and T. Reichler, 2007: Expansion of the Hadley cell under global warming. Geophys. Res. Lett., 34, L06805, doi:10.1029/2006GL028443.
Lu, J., , C. Deser, , and T. Reichler, 2009: Cause of the widening of the tropical belt since 1958. Geophys. Res. Lett., 36, L03803, doi:10.1029/2008GL036076.
Lucas, C., , B. Timbal, , and H. Nguyen, 2013: The expanding tropics: A critical assessment of the observational and modeling studies. Wiley Interdiscip. Rev.: Climatic Change,5, 89–112, doi:10.1002/wcc.251.
McLandress, C., , T. G. Shepherd, , J. F. Scinocca, , D. A. Plummer, , M. Sigmond, , A. I. Jonsson, , and M. C. Reader, 2011: Separating the dynamical effects of climate change and ozone depletion. Part II: Southern Hemisphere troposphere. J. Climate, 24, 1850–1868.
Meehl, G. A., , C. Covey, , K. E. Taylor, , T. Delworth, , R. J. Stouffer, , M. Latif, , B. McAvaney, , and J. F. B. Mitchell, 2007: THE WCRP CMIP3 multimodel dataset: A new era in climate change research. Bull. Amer. Meteor. Soc., 88, 1383–1394.
Nguyen, H., , A. Evans, , C. Lucas, , I. Smith, , and B. Timbal, 2013: The Hadley circulation in reanalyses: Climatology, variability, and change. J. Climate,26, 3357–3376.
Polvani, L., , D. Waugh, , G. Correa, , and S.-W. Son, 2011: Stratospheric ozone depletion: The main driver of twentieth-century atmospheric circulation changes in the Southern Hemisphere. J. Climate, 24, 795–812.
Previdi, M., , and B. G. Liepert, 2007: Annular modes and Hadley cell expansion under global warming. Geophys. Res. Lett., 34, L22701, doi:10.1029/2007GL031243.
Quan, X.-W., , H. F. Diaz, , and M. P. Hoerling, 2004: Change of the tropical Hadley cell since 1950. The Hadley Circulation: Present, Past and Future, H. F. Diaz and R. S. Bradley, Eds., Kluwer Academic, 85–120.
Santer, B., and Coauthors, 2003: Contributions of anthropogenic and natural forcing to recent tropopause height changes. Science, 301, 479–483, doi:10.1126/science.1084123.
Seidel, D., , and W. Randel, 2007: Recent widening of the tropical belt: Evidence from tropopause observations. J. Geophys. Res., 112, D20113, doi:10.1029/2007JD008861.
Seidel, D., , Q. Fu, , W. Randel, , and T. Reichler, 2008: Widening of the tropical belt in a changing climate. Nat. Geosci., 1, 21–24.
Staten, P., , J. Rutz, , T. Reichler, , and J. Lu, 2011: Breaking down the tropospheric circulation response by forcing. Climate Dyn., 39, 2361–2375, doi:10.1007/s00382-011-1267-y.
Taylor, K. E., , R. J. Stouffer, , and G. A. Meehl, 2012: An overview of CMIP5 and the experiment design. Bull. Amer. Meteor. Soc., 93, 485–498.
UNEP, 2007: Fighting climate change: Human solidarity in a divided world. United Nations Development Programme Human Development Rep. 2007/08, 384 pp.
WEF, 2011: Water Security: The Water-Food-Energy-Climate Nexus: The World Economic Forum Water Initiative. Island Press, 243 pp.