skip to main content

DOE PAGESDOE PAGES

Title: Forcing, feedbacks and climate sensitivity in CMIP5 coupled atmosphere-ocean climate models

We quantify forcing and feedbacks across available CMIP5 coupled atmosphere-ocean general circulation models (AOGCMs) by analysing simulations forced by an abrupt quadrupling of atmospheric carbon dioxide concentration. This is the first application of the linear forcing-feedback regression analysis of Gregory et al. (2004) to an ensemble of AOGCMs. The range of equilibrium climate sensitivity is 2.1–4.7 K. Differences in cloud feedbacks continue to be important contributors to this range. Some models show small deviations from a linear dependence of top-of-atmosphere radiative fluxes on global surface temperature change. We show that this phenomenon largely arises from shortwave cloud radiative effects over the ocean and is consistent with independent estimates of forcing using fixed sea-surface temperature methods. Moreover, we suggest that future research should focus more on understanding transient climate change, including any time-scale dependence of the forcing and/or feedback, rather than on the equilibrium response to large instantaneous forcing.
Authors:
 [1] ;  [2] ;  [1] ;  [3]
  1. Met Office Hadley Centre, Exeter (United Kingdom)
  2. Met Office Hadley Centre, Exeter (United Kingdom); Univ. of Reading, Reading (United Kingdom)
  3. Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
Publication Date:
OSTI Identifier:
1239215
Report Number(s):
LLNL-JRNL--517031
Journal ID: ISSN 0094-8276
Grant/Contract Number:
AC52-07NA27344
Type:
Accepted Manuscript
Journal Name:
Geophysical Research Letters
Additional Journal Information:
Journal Volume: 39; Journal Issue: 9; Journal ID: ISSN 0094-8276
Publisher:
American Geophysical Union
Research Org:
Lawrence Livermore National Laboratory (LLNL), Livermore, CA (United States)
Sponsoring Org:
USDOE
Country of Publication:
United States
Language:
English
Subject:
54 ENVIRONMENTAL SCIENCES; 58 GEOSCIENCES