TY - JOUR
T1 - Stability of the Atlantic meridional overturning circulation
T2 - A model intercomparison
AU - Weaver, Andrew J.
AU - Sedláček, Jan
AU - Eby, Michael
AU - Alexander, Kaitlin
AU - Crespin, Elisabeth
AU - Fichefet, Thierry
AU - Philippon-Berthier, Gwenaëlle
AU - Joos, Fortunat
AU - Kawamiy, Michio
AU - Matsumoto, Katsumi
AU - Steinacher, Marco
AU - Tachiiri, Kaoru
AU - Tokos, Kathy
AU - Yoshimori, Masakazu
AU - Zickfeld, Kirsten
PY - 2012/10/28
Y1 - 2012/10/28
N2 - The evolution of the Atlantic Meridional Overturning Circulation (MOC) in 30 models of varying complexity is examined under four distinct Representative Concentration Pathways. The models include 25 Atmosphere-Ocean General Circulation Models (AOGCMs) or Earth System Models (ESMs) that submitted simulations in support of the 5th phase of the Coupled Model Intercomparison Project (CMIP5) and 5 Earth System Models of Intermediate Complexity (EMICs). While none of the models incorporated the additional effects of ice sheet melting, they all projected very similar behaviour during the 21st century. Over this period the strength of MOC reduced by a best estimate of 22% (18%-25%; 5%-95% confidence limits) for RCP2.6, 26% (23%-30%) for RCP4.5, 29% (23%-35%) for RCP6.0 and 40% (36%-44%) for RCP8.5. Two of the models eventually realized a slow shutdown of the MOC under RCP8.5, although no model exhibited an abrupt change of the MOC. Through analysis of the freshwater flux across 30°-32°S into the Atlantic, it was found that 40% of the CMIP5 models were in a bistable regime of the MOC for the duration of their RCP integrations. The results support previous assessments that it is very unlikely that the MOC will undergo an abrupt change to an off state as a consequence of global warming.
AB - The evolution of the Atlantic Meridional Overturning Circulation (MOC) in 30 models of varying complexity is examined under four distinct Representative Concentration Pathways. The models include 25 Atmosphere-Ocean General Circulation Models (AOGCMs) or Earth System Models (ESMs) that submitted simulations in support of the 5th phase of the Coupled Model Intercomparison Project (CMIP5) and 5 Earth System Models of Intermediate Complexity (EMICs). While none of the models incorporated the additional effects of ice sheet melting, they all projected very similar behaviour during the 21st century. Over this period the strength of MOC reduced by a best estimate of 22% (18%-25%; 5%-95% confidence limits) for RCP2.6, 26% (23%-30%) for RCP4.5, 29% (23%-35%) for RCP6.0 and 40% (36%-44%) for RCP8.5. Two of the models eventually realized a slow shutdown of the MOC under RCP8.5, although no model exhibited an abrupt change of the MOC. Through analysis of the freshwater flux across 30°-32°S into the Atlantic, it was found that 40% of the CMIP5 models were in a bistable regime of the MOC for the duration of their RCP integrations. The results support previous assessments that it is very unlikely that the MOC will undergo an abrupt change to an off state as a consequence of global warming.
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U2 - 10.1029/2012GL053763
DO - 10.1029/2012GL053763
M3 - Article
AN - SCOPUS:84868325973
SN - 0094-8276
VL - 39
JO - Geophysical Research Letters
JF - Geophysical Research Letters
IS - 20
M1 - L20709
ER -