Abstract
Estimates of Equilibrium Climate Sensitivity (ECS)—the temperature with a doubling of CO2—usually are between 1.5 °C and 5 °C warming, with a mid-range/most likely value close to 3 °C. Notably, comparisons of simulations of temperature changes over the past millennium with paleoreconstructions of past temperatures tend to suggest an ECS value toward the lower end of the range closer to 2 °C, which deserves closer scrutiny. In this chapter, I review evidence that paleoreconstructions may selectively underestimate the cooling signal associated with large explosive volcanic eruptions of the past millennium, due to their reliance on tree-ring data from tree-line-proximal environments. Once large volcanic episodes are masked, these comparisons instead support a mid-range of ~3 °C of ECS. Regardless of the reason for the model/paleodata discrepancy, ECS estimates—I argue—should not rely on comparisons that include these episodes.
References
Ammann, Caspar M., and Eugene R. Wahl. 2007. The Importance of the Geophysical Context in Statistical Evaluations of Climate Reconstruction Procedures. Climatic Change 85 (1–2): 71–88. https://doi.org/10.1007/s10584-007-9276-x.
Anchukaitis, Kevin J., Petra Breitenmoser, Keith R. Briffa, Agata Buchwal, Ulf Büntgen, Edward R. Cook, Rosanne D. D’Arrigo, et al. 2012. Tree Rings and Volcanic Cooling. Nature Geoscience 5: 836–837. https://doi.org/10.1038/ngeo1645.
Andreae, Meinrat O., Chris D. Jones, and Peter M. Cox. 2005. Strong Present-Day Aerosol Cooling Implies a Hot Future. Nature 435 (7046): 1187–1191.
Büntgen, Ulf, Lukas Wacker, Kurt Nicolussi, Michael Sigl, Dominik Güttler, Willy Tegel, Paul J. Krusic, and Jan Esper. 2014. Extraterrestrial Confirmation of Tree-Ring Dating. Nature Climate Change 4: 404–405. https://doi.org/10.1038/nclimate2240.
D’Arrigo, Rosanne, Rob Wilson, and Gordon Jacoby. 2006. On the Long-Term Context for Late Twentieth Century Warming. Journal of Geophysical Research (Atmospheres) 111: D03103. https://doi.org/10.1029/2005JD006352.
Emile-Geay, J., R. Seager, M.A. Cane, E.C. Cook, and G.J. Jaug. 2008. Volcanoes and ENSO Over the Past Millennium. Journal of Climate 21: 3134–3148.
Hegerl, Gabriele C., Thomas J. Crowley, William T. Hyde, and David J. Frame. 2006. Climate Sensitivity Constrained by Temperature Reconstructions over the Past Seven Centuries. Nature 440 (7087): 1029–1032. https://doi.org/10.1038/nature04679.
Jansen, Eystein, Jonathan Overpeck, and Keith R. Briffa. 2007. Paleoclimate. In Climate Change 2007: The Physical Science Basis. Working Contribution of Working Group 1 to the Fourth Assesment Report of the Intergovernmental Panel on Climate Change. Cambridge/New York: Cambridge University Press.
Jones, P.D., and M.E. Mann. 2004. Climate over Past Millennia. Reviews of Geophysics 42 (2): RG2002. https://doi.org/10.1029/2003RG000143.
Knutti, Reto, and Gabriele C. Hegerl. 2008. The Equilibrium Sensitivity of the Earth’s Temperature to Radiation Changes. Nature Geoscience 1: 735–743. https://doi.org/10.1038/ngeo337.
Mann, Michael E. 2014. False Hope: The Rate of Global Temperature Rise May Have Hit a Plateau, but a Climate Crisis Still Looms in the Near Future. Scientific American 310: 78–81. https://doi.org/10.1038/scientificamerican0414-78.
Mann, Michael E., Jose D. Fuentes, and Scott Rutherford. 2012a. Underestimation of Volcanic Cooling in Tree-Ring-Based Reconstructions of Hemispheric Temperatures. Nature Geoscience 5: 202–205. https://doi.org/10.1038/ngeo1394.
———. 2012b. Reply to ‘Tree-Rings and Volcanic Cooling’. Nature Geoscience 5 (12): 837–838.
Mann, Michael E., Scott Rutherford, Andrew Schurer, Simon F.B. Tett, and Jose D. Fuentes. 2013. Discrepancies Between the Modeled and Proxy-Reconstructed Response to Volcanic Forcing over the Past Millennium: Implications and Possible Mechanisms. Journal of Geophysical Research: Atmospheres 118 (14): 7617–7627. https://doi.org/10.1002/jgrd.50609.
Rohde, R., R.A. Muller, R. Jacobsen, E. Muller, S. Perlmutter, et al. 2013. A New Estimate of the Average Earth Surface Land Temperature Spanning 1753–2011. Geoinfor Geostat: An Overview 1: 1. http://static.berkeleyearth.org/papers/Results:Paper-Berkeley-Earth.pdf
Rutherford, Scott, and Michael E. Mann. 2014. Missing Tree Rings and the AD 774-775 Radiocarbon Event. Nature Climate Change 26: 648–649.
Schurer, Andrew P., Gabriele C. Hegerl, Michael E. Mann, Simon F.B. Tett, and Steven J. Phipps. 2013. Separating Forced from Chaotic Climate Variability over the Past Millennium. Journal of Climate 26 (18): 6954–6973. https://doi.org/10.1175/JCLI-D-12-00826.1.
Author information
Authors and Affiliations
Editor information
Editors and Affiliations
Rights and permissions
Copyright information
© 2018 The Author(s)
About this chapter
Cite this chapter
Mann, M.E. (2018). Reconciling Climate Model/Data Discrepancies: The Case of the ‘Trees That Didn’t Bark’. In: A. Lloyd, E., Winsberg, E. (eds) Climate Modelling. Palgrave Macmillan, Cham. https://doi.org/10.1007/978-3-319-65058-6_7
Download citation
DOI: https://doi.org/10.1007/978-3-319-65058-6_7
Published:
Publisher Name: Palgrave Macmillan, Cham
Print ISBN: 978-3-319-65057-9
Online ISBN: 978-3-319-65058-6
eBook Packages: Earth and Environmental ScienceEarth and Environmental Science (R0)