Uncertainty in the Evolution of Climate Feedback Traced to the Strength of the Atlantic Meridional Overturning Circulation
Journal
Geophysical Research Letters
Journal Volume
46
Journal Issue
21
Pages
12331-12339
Date Issued
2019
Author(s)
Abstract
In most coupled climate models, effective climate sensitivity increases for a few decades following an abrupt CO2 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 CO2. 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. ©2019. American Geophysical Union. All Rights Reserved.
SDGs
Other Subjects
Carbon dioxide; Climate models; Feedback; Oceanography; Atlantic meridional overturning circulations; Climate feedbacks; Climate sensitivity; Cloud feedbacks; Coupled climate model; Lapse rate; Northern Hemispheres; Ocean circulation; Climate change; air-sea interaction; carbon dioxide; climate change; climate feedback; climate modeling; meridional circulation; Northern Hemisphere; troposphere; uncertainty analysis
Type
journal article