Earths Climate Sensitivity: Apparent Inconsistencies in Recent Assessments

Schwartz, Stephen E.; Charlson, Robert J.; Kahn, Ralph; Rodhe, Henning

doi:10.1002/2014EF000273

Title: Earths Climate Sensitivity: Apparent Inconsistencies in Recent Assessments

Journal Article · Mon Dec 08 00:00:00 EST 2014 · Earth's Future

DOI:https://doi.org/10.1002/2014EF000273· OSTI ID:1167429

Schwartz, Stephen E. ^[1]; Charlson, Robert J. ^[2]; Kahn, Ralph ^[3]; Rodhe, Henning ^[4]

Brookhaven National Laboratory (BNL), Upton, NY (United States)
Univ. of Washington, Seattle, WA (United States)
NASA Goddard Space Flight Center (GSFC), Greenbelt, MD (United States)
Stockholm Univ. (Sweden)

Earth's equilibrium climate sensitivity (ECS) and forcing of Earth's climate system over the industrial era have been re-examined in two new assessments: the Fifth Assessment Report (AR5) of the Intergovernmental Panel on Climate Change (IPCC), and a study by Otto et al. (2013). The ranges of these quantities given in these assessments and also in the Fourth (2007) IPCC Assessment are analyzed here within the framework of a planetary energy balance model, taking into account the observed increase in global mean surface temperature over the instrumental record together with best estimates of the rate of increase of planetary heat content. This analysis shows systematic differences among the several assessments and apparent inconsistencies within individual assessments. Importantly, the likely range of ECS to doubled CO₂ given in AR5, 1.5–4.5 K/(3.7 W m⁻²) exceeds the range inferred from the assessed likely range of forcing, 1.2–2.9 K/(3.7 W m⁻²), where 3.7 W ⁻² denotes the forcing for doubled CO₂. Such differences underscore the need to identify their causes and reduce the underlying uncertainties. Explanations might involve underestimated negative aerosol forcing, overestimated total forcing, overestimated climate sensitivity, poorly constrained ocean heating, limitations of the energy balance model, or a combination of effects.

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Research Organization:: Brookhaven National Laboratory (BNL), Upton, NY (United States)

Sponsoring Organization:: USDOE Office of Science (SC)

Grant/Contract Number:: SC00112704

OSTI ID:: 1167429

Report Number(s):: BNL-107119-2014-JA; R&D Project: 2016-BNL-EE630EECA-Budg; KP1701000

Journal Information:: Earth's Future, Vol. 2, Issue 12; ISSN 2328-4277

Publisher:: American Geophysical Union (AGU)Copyright Statement

Country of Publication:: United States

Language:: English

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Cited by: 13 works

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References (15)

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Cited By (4)

Beyond equilibrium climate sensitivity Knutti, Reto; Rugenstein, Maria A. A.; Hegerl, Gabriele C. Nature Geoscience, Vol. 10, Issue 10 https://doi.org/10.1038/ngeo3017	journal	September 2017
Analysis algorithm for sky type and ice halo recognition in all-sky images Boyd, Sylke; Sorenson, Stephen; Richard, Shelby Atmospheric Measurement Techniques, Vol. 12, Issue 8 https://doi.org/10.5194/amt-12-4241-2019	journal	January 2019
Beyond equilibrium climate sensitivity Knutti, Reto; Rugenstein, Maria A. A.; Hegerl, Gabriele C. ETH Zurich https://doi.org/10.3929/ethz-b-000197761	text	January 2017
Analysis Algorithm for Sky Type and Ice Halo Recognition in All-Sky Images Boyd, Sylke; Sorenson, Stephen; Richard, Shelby Atmospheric Measurement Techniques Discussions https://doi.org/10.5194/amt-2018-401	posted_content	January 2019

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