- Email: [email protected]
Corrigendum to “On a minimal model for estimating climate sensitivity” [Ecol. Model. 297 (2015) 20–25]
Ecological Modelling 312 (2015) 102–103
Contents lists available at ScienceDirect
Ecological Modelling journal homepage: www.elsevier.com/locate/ecolmodel
Corrigendum
Corrigendum to “On a minimal model for estimating climate sensitivity” [Ecol. Model. 297 (2015) 20–25] Gavin C. Cawley a,∗ , Kevin Cowtan b , Robert G. Way c , Peter Jacobs d , Ari Jokimäki e a
School of Computing Sciences, University of East Anglia, Norwich, UK Department of Chemistry, University of York, York, UK Department of Geography, University of Ottawa, Ottawa, Canada d Department of Environmental Science and Policy, George Mason University, Fairfax, VA, USA e Skeptical Science, Brisbane, Australia b c
The authors regret that Section 1.4 of our paper (Cawley et al., 2015) contains an error; the estimates of equilibrium climate sensitivity and transient climate sensitivity should have been divided, rather than multiplied by 1.145. However, this does not substantially alter the conclusion that the curve-fitting approach, adopted by Loehle, does not provide a reliable means of estimating climate sensitivity. Fig. 1 shows the ranges of transient climate response from the paper by Loehle (2014), the corrected estimate from the revised Loehle model described in Cawley et al. (2015), the IPCC AR5 likely range (IPCC, 2013, Box 12.2), the CMIP5 ensemble estimate (IPCC, 2013, Table 9.5) and estimates from the papers by Otto et al. (2013) and Shindell (2014) to provide context. The range of values for TCR for the original and revised Loehle models remain very different. The revised Loehle model gives a range for TCR that is very similar to the expert assessed likely range given in the IPCC AR5 WG1 report. The revised Loehle model suggests that values of TCR slightly less than those of the CMIP5 ensemble of general circulation models are plausible, however a number of previous studies have also suggested plausible values for the TCR both lower (e.g. Fig. 1 Otto et al. 2013 (2000s)) and higher (e.g. Fig. 1 Otto et al. 2013 (1970–2009)) than the CMIP5 ensemble range, and this is already taken into consideration in deriving the IPCC likely range. At least one subsequent study Shindell (2014) suggests plausible values of TCR in excess of the IPCC likely range. It is our view that the cyclic model (Cawley et al., 2015; Craig Loehle, 2014)
Fig. 1. Estimates of the plausible range of transient climate response (TCR) (Craig Loehle, 2014; Cawley et al., 2015; IPCC, 2013; Otto et al., 2013; Shindell, 2014).
DOI of original article: http://dx.doi.org/10.1016/j.ecolmodel.2014.10.018. ∗ Corresponding author. Email: [email protected]. E-mail address: [email protected] (G.C. Cawley). http://dx.doi.org/10.1016/j.ecolmodel.2015.05.003 0304-3800/© 2015 Elsevier B.V. All rights reserved.
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provides little support for significant revision of the mainstream scientific assessment of climate sensitivity (as represented by the IPCC likely range for TCS of 1–2.5 ◦ C and ECS of 1.5–4.5 ◦ C), for three reasons: Firstly, the revised model remains subject to omitted variable bias and hence is inherently biased towards underestimating climate sensitivity. Secondly, the revised model does not address all of the unrealistic assumptions of the original model, for instance that the net anthropogenic influence on climate prior to 1950 was uniformly negligible or that volcanic activity can be treated as noise, neither of which are likely to be true (c.f. Cawley et al., 2015 [Fig. 3(a) and (c)]). Lastly, the components of the model are only speculatively identified with a “long-term warming since the Little Ice age”, the Atlantic Multidecadal Oscillation (AMO) and Pacific Decadal Oscillation (PDO) and/or the periodic behaviour of solar activity, without reference to the observations of these phenomena. However, a more rigorous model with a stronger physical basis which supports the plausibility of low climate sensitivity (or better still, ruled out high climate sensitivity) would be most welcome. We thank Mark Richardson for first bringing this error to our attention, and Nicholas Lewis for also raising this issue. References Craig Loehle, A., 2014. minimal model for estimating climate sensitivity. Ecol. Model. 276, 80–84, http://dx.doi.org/10.1016/j.ecolmodel.2014.01.006 Cawley, G.C., Cowtan, K., Way, R.G., Jacobs, P., Jokimäki, A., 2015. On a minimal model for estimating climate sensitivity. Ecol. Model. 297, 20–25, http://dx.doi.org/10.1016/j. ecolmodel.2014.10.018 IPCC, 2013. Climate change 2013: the physical science basis. In: Stocker, T.F., Qin, D., Plattner, G.-K., Tignor, M., Allen, S.K., Boschung, J., Nauels, A., Xia, Y., Bex, V., Midgley, P.M. (Eds.), Contribution of Working Group I to the Fifth Assessment Report of the Intergovernmental Panel on Climate Change. Cambridge University Press, Cambridge, United Kingdom and New York, NY, USA, 1535 pp. Otto, A., Otto, F.E.L., Boucher, O., Church, J., Hegerl, G., Forster, P.M., Gillett, N.P., Gregory, J., Johnson, G.C., Knutti, R., Lewis, N., Lohmann, U., Marotzke, J., Myhre, G., Shindell, D., Stevens, B., Allen, M.R., 2013. Energy budget constraints on climate response. Nat. Geosci. 6 (6), 415–416, http://dx.doi.org/10.1038/ngeo.1836 Shindell, D.T., 2014. Inhomogenous forcing and transient climate sensitivity. Nat. Clim. Change 4, 274–277, http://dx.doi.org/10.1038/NCLIMATE2136.
Contents lists available at ScienceDirect
Ecological Modelling journal homepage: www.elsevier.com/locate/ecolmodel
Corrigendum
Corrigendum to “On a minimal model for estimating climate sensitivity” [Ecol. Model. 297 (2015) 20–25] Gavin C. Cawley a,∗ , Kevin Cowtan b , Robert G. Way c , Peter Jacobs d , Ari Jokimäki e a
School of Computing Sciences, University of East Anglia, Norwich, UK Department of Chemistry, University of York, York, UK Department of Geography, University of Ottawa, Ottawa, Canada d Department of Environmental Science and Policy, George Mason University, Fairfax, VA, USA e Skeptical Science, Brisbane, Australia b c
The authors regret that Section 1.4 of our paper (Cawley et al., 2015) contains an error; the estimates of equilibrium climate sensitivity and transient climate sensitivity should have been divided, rather than multiplied by 1.145. However, this does not substantially alter the conclusion that the curve-fitting approach, adopted by Loehle, does not provide a reliable means of estimating climate sensitivity. Fig. 1 shows the ranges of transient climate response from the paper by Loehle (2014), the corrected estimate from the revised Loehle model described in Cawley et al. (2015), the IPCC AR5 likely range (IPCC, 2013, Box 12.2), the CMIP5 ensemble estimate (IPCC, 2013, Table 9.5) and estimates from the papers by Otto et al. (2013) and Shindell (2014) to provide context. The range of values for TCR for the original and revised Loehle models remain very different. The revised Loehle model gives a range for TCR that is very similar to the expert assessed likely range given in the IPCC AR5 WG1 report. The revised Loehle model suggests that values of TCR slightly less than those of the CMIP5 ensemble of general circulation models are plausible, however a number of previous studies have also suggested plausible values for the TCR both lower (e.g. Fig. 1 Otto et al. 2013 (2000s)) and higher (e.g. Fig. 1 Otto et al. 2013 (1970–2009)) than the CMIP5 ensemble range, and this is already taken into consideration in deriving the IPCC likely range. At least one subsequent study Shindell (2014) suggests plausible values of TCR in excess of the IPCC likely range. It is our view that the cyclic model (Cawley et al., 2015; Craig Loehle, 2014)
Fig. 1. Estimates of the plausible range of transient climate response (TCR) (Craig Loehle, 2014; Cawley et al., 2015; IPCC, 2013; Otto et al., 2013; Shindell, 2014).
DOI of original article: http://dx.doi.org/10.1016/j.ecolmodel.2014.10.018. ∗ Corresponding author. Email: [email protected]. E-mail address: [email protected] (G.C. Cawley). http://dx.doi.org/10.1016/j.ecolmodel.2015.05.003 0304-3800/© 2015 Elsevier B.V. All rights reserved.
G.C. Cawley et al. / Ecological Modelling 312 (2015) 102–103
103
provides little support for significant revision of the mainstream scientific assessment of climate sensitivity (as represented by the IPCC likely range for TCS of 1–2.5 ◦ C and ECS of 1.5–4.5 ◦ C), for three reasons: Firstly, the revised model remains subject to omitted variable bias and hence is inherently biased towards underestimating climate sensitivity. Secondly, the revised model does not address all of the unrealistic assumptions of the original model, for instance that the net anthropogenic influence on climate prior to 1950 was uniformly negligible or that volcanic activity can be treated as noise, neither of which are likely to be true (c.f. Cawley et al., 2015 [Fig. 3(a) and (c)]). Lastly, the components of the model are only speculatively identified with a “long-term warming since the Little Ice age”, the Atlantic Multidecadal Oscillation (AMO) and Pacific Decadal Oscillation (PDO) and/or the periodic behaviour of solar activity, without reference to the observations of these phenomena. However, a more rigorous model with a stronger physical basis which supports the plausibility of low climate sensitivity (or better still, ruled out high climate sensitivity) would be most welcome. We thank Mark Richardson for first bringing this error to our attention, and Nicholas Lewis for also raising this issue. References Craig Loehle, A., 2014. minimal model for estimating climate sensitivity. Ecol. Model. 276, 80–84, http://dx.doi.org/10.1016/j.ecolmodel.2014.01.006 Cawley, G.C., Cowtan, K., Way, R.G., Jacobs, P., Jokimäki, A., 2015. On a minimal model for estimating climate sensitivity. Ecol. Model. 297, 20–25, http://dx.doi.org/10.1016/j. ecolmodel.2014.10.018 IPCC, 2013. Climate change 2013: the physical science basis. In: Stocker, T.F., Qin, D., Plattner, G.-K., Tignor, M., Allen, S.K., Boschung, J., Nauels, A., Xia, Y., Bex, V., Midgley, P.M. (Eds.), Contribution of Working Group I to the Fifth Assessment Report of the Intergovernmental Panel on Climate Change. Cambridge University Press, Cambridge, United Kingdom and New York, NY, USA, 1535 pp. Otto, A., Otto, F.E.L., Boucher, O., Church, J., Hegerl, G., Forster, P.M., Gillett, N.P., Gregory, J., Johnson, G.C., Knutti, R., Lewis, N., Lohmann, U., Marotzke, J., Myhre, G., Shindell, D., Stevens, B., Allen, M.R., 2013. Energy budget constraints on climate response. Nat. Geosci. 6 (6), 415–416, http://dx.doi.org/10.1038/ngeo.1836 Shindell, D.T., 2014. Inhomogenous forcing and transient climate sensitivity. Nat. Clim. Change 4, 274–277, http://dx.doi.org/10.1038/NCLIMATE2136.