Why Hasn’t Earth Warmed as Much as Expected?

Stephen E. Schwartz Brookhaven National Laboratory, Upton, New York

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Robert J. Charlson University of Washington, Seattle, Washington

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Ralph A. Kahn NASA Goddard Space Flight Center, Greenbelt, Maryland

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John A. Ogren NOAA/Earth System Research Laboratory, Boulder, Colorado

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Henning Rodhe Department of Meteorology, Stockholm University, Stockholm, Sweden

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Abstract

The observed increase in global mean surface temperature (GMST) over the industrial era is less than 40% of that expected from observed increases in long-lived greenhouse gases together with the best-estimate equilibrium climate sensitivity given by the 2007 Assessment Report of the Intergovernmental Panel on Climate Change (IPCC). Possible reasons for this warming discrepancy are systematically examined here. The warming discrepancy is found to be due mainly to some combination of two factors: the IPCC best estimate of climate sensitivity being too high and/or the greenhouse gas forcing being partially offset by forcing by increased concentrations of atmospheric aerosols; the increase in global heat content due to thermal disequilibrium accounts for less than 25% of the discrepancy, and cooling by natural temperature variation can account for only about 15%. Current uncertainty in climate sensitivity is shown to preclude determining the amount of future fossil fuel CO2 emissions that would be compatible with any chosen maximum allowable increase in GMST; even the sign of such allowable future emissions is unconstrained. Resolving this situation, by empirical determination of the earth’s climate sensitivity from the historical record over the industrial period or through use of climate models whose accuracy is evaluated by their performance over this period, is shown to require substantial reduction in the uncertainty of aerosol forcing over this period.

Corresponding author address: Stephen E. Schwartz, Brookhaven National Laboratory, Upton, NY 11973. Email: ses@bnl.gov

A comment/reply has been published regarding this article and can be found at http://journals.ametsoc.org/doi/abs/10.1175/2011JCLI4038.1 and http://journals.ametsoc.org/doi/abs/10.1175/2011JCLI4161.1

Abstract

The observed increase in global mean surface temperature (GMST) over the industrial era is less than 40% of that expected from observed increases in long-lived greenhouse gases together with the best-estimate equilibrium climate sensitivity given by the 2007 Assessment Report of the Intergovernmental Panel on Climate Change (IPCC). Possible reasons for this warming discrepancy are systematically examined here. The warming discrepancy is found to be due mainly to some combination of two factors: the IPCC best estimate of climate sensitivity being too high and/or the greenhouse gas forcing being partially offset by forcing by increased concentrations of atmospheric aerosols; the increase in global heat content due to thermal disequilibrium accounts for less than 25% of the discrepancy, and cooling by natural temperature variation can account for only about 15%. Current uncertainty in climate sensitivity is shown to preclude determining the amount of future fossil fuel CO2 emissions that would be compatible with any chosen maximum allowable increase in GMST; even the sign of such allowable future emissions is unconstrained. Resolving this situation, by empirical determination of the earth’s climate sensitivity from the historical record over the industrial period or through use of climate models whose accuracy is evaluated by their performance over this period, is shown to require substantial reduction in the uncertainty of aerosol forcing over this period.

Corresponding author address: Stephen E. Schwartz, Brookhaven National Laboratory, Upton, NY 11973. Email: ses@bnl.gov

A comment/reply has been published regarding this article and can be found at http://journals.ametsoc.org/doi/abs/10.1175/2011JCLI4038.1 and http://journals.ametsoc.org/doi/abs/10.1175/2011JCLI4161.1

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  • Allen, M. R., and Coauthors, 2009: Warming caused by cumulative carbon emissions towards the trillionth tonne. Nature, 458 , 11631166.

    • Search Google Scholar
    • Export Citation
  • Anderson, T. L., and Coauthors, 2005: An “A-train” strategy for quantifying direct climate forcing by anthropogenic aerosols. Bull. Amer. Meteor. Soc., 86 , 17951809.

    • Search Google Scholar
    • Export Citation
  • Bates, T. S., and Coauthors, 2006: Aerosol direct radiative effects over the northwest Atlantic, northwest Pacific, and North Indian Oceans: Estimates based on in-situ chemical and optical measurements and chemical transport modeling. Atmos. Chem. Phys., 6 , 16571732.

    • Search Google Scholar
    • Export Citation
  • Boer, G. J., M. Stowasser, and K. Hamilton, 2007: Inferring climate sensitivity from volcanic events. Climate Dyn., 28 , 481502.

  • Brasseur, G. P., and E. Roeckner, 2005: Impact of improved air quality on the future evolution of climate. Geophys. Res. Lett., 32 , L23704. doi:10.1029/2005GL023902.

    • Search Google Scholar
    • Export Citation
  • Caldeira, K., A. K. Jain, and M. I. Hoffert, 2003: Climate sensitivity uncertainty and the need for energy without CO2 emission. Science, 239 , 20522054.

    • Search Google Scholar
    • Export Citation
  • Charlson, R. J., S. E. Schwartz, J. M. Hales, R. D. Cess, J. A. Coakley Jr., J. E. Hansen, and D. J. Hofmann, 1992: Climate forcing by anthropogenic aerosols. Science, 255 , 423430.

    • Search Google Scholar
    • Export Citation
  • Climate Change Science Program, 2009: Atmospheric aerosol properties and climate impacts. Synthesis and Assessment Product 2.3, 128 pp. [Available online at http://downloads.climatescience.gov/sap/sap2-3/sap2-3-final-report-all.pdf].

    • Search Google Scholar
    • Export Citation
  • Cubasch, U., and Coauthors, 2001: Projections of future climate change. Climate Change 2001: The Scientific Basis, J. T. Houghton et al., Eds., Cambridge University Press, 526–582.

    • Search Google Scholar
    • Export Citation
  • Delene, D. J., and J. A. Ogren, 2002: Variability of aerosol optical properties at four North American surface monitoring sites. J. Atmos. Sci., 59 , 11351150.

    • Search Google Scholar
    • Export Citation
  • Diner, D. J., and Coauthors, 2004: PARAGON: An integrated approach for characterizing aerosol climate impacts and environmental interactions. Bull. Amer. Meteor. Soc., 85 , 14951501.

    • Search Google Scholar
    • Export Citation
  • Domingues, C. M., J. A. Church, N. J. White, P. J. Gleckler, S. E. Wijffels, P. M. Barker, and J. R. Dunn, 2008: Improved estimates of upper-ocean warming and multi-decadal sea-level rise. Nature, 453 , 10901094.

    • Search Google Scholar
    • Export Citation
  • Douglass, D. H., and R. S. Knox, 2009: Ocean heat content and Earth’s radiation imbalance. Phys. Lett. A, 373 , 32963300.

  • Edmonds, J., and S. Smith, 2006: The technology of two degrees. Avoiding Dangerous Climate Change, H. J. Schellnhuber et al., Eds., Cambridge University Press, 385–392.

    • Search Google Scholar
    • Export Citation
  • European Union Council, cited. 1996: Community strategy on climate change—Council conclusions. 1939th Council Meeting Environment, Document 8518/96. [Available online at http://ue.eu.int/ueDocs/cms_Data/docs/pressData/en/envir/011a0006.htm].

    • Search Google Scholar
    • Export Citation
  • Forster, P. Mde F., and J. M. Gregory, 2006: The climate sensitivity and its components diagnosed from Earth Radiation Budget data. J. Climate, 19 , 3952.

    • Search Google Scholar
    • Export Citation
  • Ganopolski, A., and T. Schneider von Deimling, 2008: Comment on “Aerosol radiative forcing and climate sensitivity deduced from the Last Glacial Maximum to Holocene transition” by Petr Chylek and Ulrike Lohmann. Geophys. Res. Lett., 35 , L23703. doi:10.1029/2008GL033888.

    • Search Google Scholar
    • Export Citation
  • Ghan, S. J., and S. E. Schwartz, 2007: Aerosol properties and processes: A path from field and laboratory measurements to global climate models. Bull. Amer. Meteor. Soc., 88 , 10591083.

    • Search Google Scholar
    • Export Citation
  • Gouretski, V., and K. P. Koltermann, 2007: How much is the ocean really warming? Geophys. Res. Lett., 34 , L01610. doi:10.1029/2006GL027834.

    • Search Google Scholar
    • Export Citation
  • Gregory, J. M., R. J. Stouffer, S. C. B. Raper, P. A. Stott, and N. A. Rayner, 2002: An observationally based estimate of the climate sensitivity. J. Climate, 15 , 31173121.

    • Search Google Scholar
    • Export Citation
  • Hansen, J. E., 2008: Threat to the planet: Dark and bright sides of global warming. Eos, Trans. Amer. Geophys. Union, 89 .(Fall Meeting Suppl.). Abstract A33D-01.

    • Search Google Scholar
    • Export Citation
  • Hansen, J. E., A. Lacis, D. Rind, G. Russell, P. Stone, and I. Fung, 1984: Climate sensitivity: Analysis of feedback mechanisms. Climate Processes and Climate Sensitivity, Geophys. Monogr., Vol. 29, Amer. Geophys. Union, 130–163.

    • Search Google Scholar
    • Export Citation
  • Hansen, J. E., and Coauthors, 2005: Earth’s energy imbalance: Confirmation and implications. Science, 308 , 14311435.

  • Heintzenberg, J., and R. J. Charlson, Eds. 2009: Clouds in the Perturbed Climate System: Their Relationship to Energy Balance, Atmospheric Dynamics, and Precipitation. MIT Press, 576 pp.

    • Search Google Scholar
    • Export Citation
  • Huang, S., 2006: Land warming as part of global warming. Eos, Trans. Amer. Geophys. Union,87, pp. 477, 480.

  • Ishii, M., and M. Kimoto, 2009: Reevaluation of historical ocean heat content variations with time-varying XBT and MBT depth bias corrections. J. Oceanogr., 65 , 287299.

    • Search Google Scholar
    • Export Citation
  • Juckes, M. N., M. R. Allen, K. R. Briffa, J. Esper, G. C. Hegerl, A. Moberg, T. J. Osborn, and S. L. Weber, 2007: Millennial temperature reconstruction intercomparison and evaluation. Climate Past, 3 , 591609.

    • Search Google Scholar
    • Export Citation
  • Junge, C. E., 1975: The possible influence of aerosols on the general circulation and climate and possible approaches for modelling. The Physical Basis of Climate and Climate Modelling, Global Atmospheric Research Program (GARP), Publication 16, World Meteorological Organization, International Council of Scientific Unions Joint Organizing Committee, 244–251.

    • Search Google Scholar
    • Export Citation
  • Kahn, R. A., and Coauthors, 2004: Aerosol data sources and their roles within PARAGON. Bull. Amer. Meteor. Soc., 85 , 15111522.

  • Kahn, R. A., and Coauthors, 2009: MISR aerosol product attributes and statistical comparison with MODIS. IEEE Trans. Geosci. Remote Sens., 47 , 40954114.

    • Search Google Scholar
    • Export Citation
  • Kiehl, J. T., 2007: Twentieth century climate model response and climate sensitivity. Geophys. Res. Lett., 34 , L22710. doi:10.1029/2007GL031383.

    • Search Google Scholar
    • Export Citation
  • Kinne, S., and Coauthors, 2006: An AeroCom initial assessment optical properties in aerosol component modules of global models. Atmos. Chem. Phys., 6 , 18151834.

    • Search Google Scholar
    • Export Citation
  • Knutti, R., 2008: Why are climate models reproducing the observed global surface warming so well? Geophys. Res. Lett., 35 , L18704. doi:10.1029/2008GL034932.

    • Search Google Scholar
    • Export Citation
  • Levitus, S., J. I. Antonov, and T. P. Boyer, 2005: Warming of the world ocean, 1955–2003. Geophys. Res. Lett., 32 , L02604. doi:10.1029/2004GL021592.

    • Search Google Scholar
    • Export Citation
  • Levitus, S., J. I. Antonov, T. P. Boyer, R. A. Locarnini, H. E. Garcia, and A. V. Mishonov, 2009: Global ocean heat content 1955-2008 in light of recently revealed instrumentation problems. Geophys. Res. Lett., 36 , L07608. doi:10.1029/2008GL037155.

    • Search Google Scholar
    • Export Citation
  • Lindzen, R. S., B. Kirtman, D. Kirk-Davidoff, and E. K. Schneider, 1995: Seasonal surrogate for climate. J. Climate, 8 , 16811684.

  • Malm, W. C., B. A. Schichtel, M. L. Pitchford, L. L. Ashbaugh, and R. A. Eldred, 2004: Spatial and monthly trends in speciated fine particle concentration in the United States. J. Geophys. Res., 109 , D03306. doi:10.1029/2003JD003739.

    • Search Google Scholar
    • Export Citation
  • Matthews, H. D., and K. Caldeira, 2007: Transient climate-carbon simulations of planetary geoengineering. Proc. Natl. Acad. Sci. USA, 104 , 99499954.

    • Search Google Scholar
    • Export Citation
  • Mishchenko, M. I., and Coauthors, 2007: Accurate monitoring of terrestrial aerosols and total solar irradiance: Introducing the Glory Mission. Bull. Amer. Meteor. Soc., 88 , 677691.

    • Search Google Scholar
    • Export Citation
  • Murphy, D. M., S. Solomon, R. W. Portmann, K. H. Rosenlof, P. M. Forster, and T. Wong, 2009: An observationally based energy balance for the Earth since 1950. J. Geophys. Res., 114 , D17107. doi:10.1029/2009JD012105.

    • Search Google Scholar
    • Export Citation
  • National Research Council, 1996: A Plan for a Research Program on Aerosol Radiative Forcing and Climate Change. National Academies Press, 180 pp.

    • Search Google Scholar
    • Export Citation
  • National Research Council, 2005: Radiative Forcing of Climate Change: Expanding the Concept and Addressing Uncertainties. National Academies Press, 224 pp.

    • Search Google Scholar
    • Export Citation
  • Ramanathan, V., and Y. Feng, 2008: On avoiding dangerous anthropogenic interference with the climate system: Formidable challenges ahead. Proc. Natl. Acad. Sci. USA, 105 , 1424514250.

    • Search Google Scholar
    • Export Citation
  • Raupach, M., G. Marland, P. Ciais, C. L. Quéré, J. G. Canadell, G. Klepper, and C. Field, 2007: Global and regional drivers of accelerating CO2 emissions. Proc. Natl. Acad. Sci. USA, 104 , 1028810293.

    • Search Google Scholar
    • Export Citation
  • Roe, G. H., and M. B. Baker, 2007: Why is climate sensitivity so unpredictable? Science, 318 , 629632.

  • Sanderson, B., C. Piani, W. Ingram, D. Stone, and M. R. Allen, 2008: Towards constraining climate sensitivity by linear analysis of feedback patterns in thousands of perturbed-physics GCM simulations. Climate Dyn., 30 , 175190.

    • Search Google Scholar
    • Export Citation
  • Schlesinger, M. E., 1988: Quantitative analysis of feedbacks in climate model simulations of CO2 induced warming. Physically Based Modelling and Simulation of Climate and Climate Change, M. E. Schlesinger, Ed., NATO ASI Series C, Vol. 243, Kluwer Academic, 653–735.

    • Search Google Scholar
    • Export Citation
  • Schwartz, S. E., R. J. Charlson, and H. Rodhe, 2007: Quantifying climate change—Too rosy a picture? Nature Rep. Climate Change, 1 , 2324. doi:10.1038/climate.2007.22.

    • Search Google Scholar
    • Export Citation
  • Solomon, S., D. Qin, M. Manning, M. Marquis, K. Averyt, M. M. B. Tignor, H. L. Miller Jr., and Z. Chen, Eds. 2007: Climate Change 2007: The Physical Science Basis. Cambridge University Press, 996 pp.

    • Search Google Scholar
    • Export Citation
  • Trenberth, K., J. T. Fasullo, and J. Kiehl, 2009: Earth’s global energy budget. Bull. Amer. Meteor. Soc., 90 , 311324.

  • Wijffels, S. E., J. Willis, C. M. Domingues, P. Barker, N. J. White, A. Gronell, K. Ridgway, and J. A. Church, 2008: Changing eXpendable BathyThermograph fall-rates and their impact on estimates of thermosteric sea level rise. J. Climate, 21 , 56575672.

    • Search Google Scholar
    • Export Citation
  • Willis, J. K., D. Roemmich, and B. Cornuelle, 2004: Interannual variability in upper ocean heat content, temperature, and thermosteric expansion on global scales. J. Geophys. Res., 109 , C12036. doi:10.1029/2003JC002260.

    • Search Google Scholar
    • Export Citation
  • Yeager, A., 2008: Satellite risks losing sight of Earth. Nature, 456 , 292.

  • Yu, H., and Coauthors, 2006: A review of measurement-based assessment of aerosol direct radiative effect and forcing. Atmos. Chem. Phys., 6 , 613666.

    • Search Google Scholar
    • Export Citation
  • Zhang, Q., and Coauthors, 2007: Ubiquity and dominance of oxygenated species in organic aerosols in anthropogenically-influenced Northern Hemisphere midlatitudes. Geophys. Res. Lett., 34 , L13801. doi:10.1029/2007GL029979.

    • Search Google Scholar
    • Export Citation
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