Relationship of tropospheric stability to climate sensitivity and Earth's observed radiation budget
File(s)ceppi_and_gregory_revised.pdf (12.32 MB)
Accepted version
Author(s)
Ceppi, Paulo
Gregory, Jonathan M
Type
Journal Article
Abstract
Climate feedbacks generally become smaller in magnitude over time under CO2 forcing in coupled climate models, leading to an increase in the effective climate sensitivity, the estimated global-mean surface warming in steady state for doubled CO2. Here, we show that the evolution of climate feedbacks in models is consistent with the effect of a change in tropospheric stability, as has recently been hypothesized, and the latter is itself driven by the evolution of the pattern of sea-surface temperature response. The change in climate feedback is mainly associated with a decrease in marine tropical low cloud (a more positive shortwave cloud feedback) and with a less negative lapse-rate feedback, as expected from a decrease in stability. Smaller changes in surface albedo and humidity feedbacks also contribute to the overall change in feedback, but are unexplained by stability. The spatial pattern of feedback changes closely matches the pattern of stability changes, with the largest increase in feedback occurring in the tropical East Pacific. Relationships qualitatively similar to those in the models among sea-surface temperature pattern, stability, and radiative budget are also found in observations on interannual time scales. Our results suggest that constraining the future evolution of sea-surface temperature patterns and tropospheric stability will be necessary for constraining climate sensitivity.
Date Issued
2017-12-12
Date Acceptance
2017-11-03
Citation
Proceedings of the National Academy of Sciences of the United States of America, 2017, 114 (50), pp.13126-13131
ISSN
0027-8424
Publisher
National Academy of Sciences
Start Page
13126
End Page
13131
Journal / Book Title
Proceedings of the National Academy of Sciences of the United States of America
Volume
114
Issue
50
Copyright Statement
© 2017 Published under the PNAS license.
Identifier
http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcApp=PARTNER_APP&SrcAuth=LinksAMR&KeyUT=WOS:000417806200047&DestLinkType=FullRecord&DestApp=ALL_WOS&UsrCustomerID=1ba7043ffcc86c417c072aa74d649202
Subjects
Science & Technology
Multidisciplinary Sciences
Science & Technology - Other Topics
climate feedbacks
climate sensitivity
radiative budget
clouds
climate change
SURFACE-TEMPERATURE-CHANGE
OCEAN HEAT UPTAKE
LOW-CLOUD COVER
EVOLVING PATTERNS
SPATIAL-PATTERN
ENERGY BUDGET
FEEDBACK
DEPENDENCE
MODEL
Publication Status
Published
Date Publish Online
2017-11-28