Richardson, TB orcid.org/0000-0002-3947-9915, Forster, PM orcid.org/0000-0002-6078-0171, Smith, CJ orcid.org/0000-0003-0599-4633 et al. (21 more authors) (2019) Efficacy of Climate Forcings in PDRMIP Models. Journal of Geophysical Research: Atmospheres, 124 (23). pp. 12824-12844. ISSN 2169-897X
Abstract
Quantifying the efficacy of different climate forcings is important for understanding the real‐world climate sensitivity. This study presents a systematic multimodel analysis of different climate driver efficacies using simulations from the Precipitation Driver and Response Model Intercomparison Project (PDRMIP). Efficacies calculated from instantaneous radiative forcing deviate considerably from unity across forcing agents and models. Effective radiative forcing (ERF) is a better predictor of global mean near‐surface air temperature (GSAT) change. Efficacies are closest to one when ERF is computed using fixed sea surface temperature experiments and adjusted for land surface temperature changes using radiative kernels. Multimodel mean efficacies based on ERF are close to one for global perturbations of methane, sulfate, black carbon, and insolation, but there is notable intermodel spread. We do not find robust evidence that the geographic location of sulfate aerosol affects its efficacy. GSAT is found to respond more slowly to aerosol forcing than CO2 in the early stages of simulations. Despite these differences, we find that there is no evidence for an efficacy effect on historical GSAT trend estimates based on simulations with an impulse response model, nor on the resulting estimates of climate sensitivity derived from the historical period. However, the considerable intermodel spread in the computed efficacies means that we cannot rule out an efficacy‐induced bias of ±0.4 K in equilibrium climate sensitivity to CO2 doubling when estimated using the historical GSAT trend.
Metadata
Item Type: | Article |
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Authors/Creators: |
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Copyright, Publisher and Additional Information: | © 2019, The Authors. This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited. To view a copy of this license, visit http://creativecommons.org/licenses/by/4.0/. |
Keywords: | Efficacy; Climate Sensitivity; Radiative Forcing; Surface temperature; PDRMIP |
Dates: |
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Institution: | The University of Leeds |
Academic Units: | The University of Leeds > Faculty of Environment (Leeds) > School of Earth and Environment (Leeds) > Inst for Climate & Atmos Science (ICAS) (Leeds) |
Funding Information: | Funder Grant number NERC NE/M018199/1 EU - European Union 820829 NERC NE/N006038/1 |
Depositing User: | Symplectic Publications |
Date Deposited: | 26 Nov 2019 11:59 |
Last Modified: | 22 Jan 2020 09:23 |
Status: | Published |
Publisher: | American Geophysical Union |
Identification Number: | 10.1029/2019JD030581 |
Open Archives Initiative ID (OAI ID): | oai:eprints.whiterose.ac.uk:153863 |
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