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Uncertainty in the Evolution of Climate Feedback Traced to the Strength of the Atlantic Meridional Overturning Circulation
Author(s) -
Lin YuanJen,
Hwang YenTing,
Ceppi Paulo,
Gregory Jonathan M.
Publication year - 2019
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/2019gl083084
Subject(s) - climatology , northern hemisphere , climate sensitivity , zonal and meridional , climate model , climate change , environmental science , thermohaline circulation , climate system , climate state , circulation (fluid dynamics) , shortwave , general circulation model , ocean current , troposphere , shutdown of thermohaline circulation , atmospheric sciences , geology , global warming , oceanography , effects of global warming , north atlantic deep water , physics , radiative transfer , quantum mechanics , thermodynamics
In most coupled climate models, effective climate sensitivity increases for a few decades following an abrupt CO 2 increase. The change in the climate feedback parameter between the first 20 years and the subsequent 130 years is highly model dependent. In this study, we suggest that the intermodel spread of changes in climate feedback can be partially traced to the evolution of the Atlantic Meridional Overturning Circulation. Models with stronger Atlantic Meridional Overturning Circulation recovery tend to project more amplified warming in the Northern Hemisphere a few decades after a quadrupling of CO 2 . Tropospheric stability then decreases as the Northern Hemisphere gets warmer, which leads to an increase in both the lapse‐rate and shortwave cloud feedbacks. Our results suggest that constraining future ocean circulation changes will be necessary for accurate climate sensitivity projections.