NASA Logo

NTRS

NTRS - NASA Technical Reports Server

Back to Results
Asymmetric Warming/Cooling Response to CO2 Increase/Decrease Mainly Due to Non-Logarithmic Forcing, not FeedbacksWe explore the CO2 dependence of effective climate sensitivity (SG) with symmetric abrupt and transient CO2 forcing, spanning the range 1/8×, 1/4×, 1/2×, 2×, 4×, and 8×CO2, using two state-of-the-art fully coupled atmosphere-ocean-sea-ice-land models. In both models, under abrupt CO2 forcing, we find an asymmetric response in surface temperature and SG. The surface global warming at 8×CO2 is more than one third larger than the corresponding cooling at 1/8×CO2, and SG is CO2 dependent, increasing non-monotonically from 1/8×CO2 to 8×CO2. We find similar CO2 dependence in the transient runs, forced with -1%yr−1CO2 and +1%yr−1CO2 up to 1/8×CO2 and 8×CO2, respectively. The non-logarithmic radiative forcing – not the changing feedbacks – primarily explains the dependence of SG on CO2, particularly at low CO2 levels. The changing feedbacks, however, explain SG’s non-monotonic behavior.
Document ID
20220003140
Acquisition Source
Goddard Space Flight Center
Document Type
Accepted Manuscript (Version with final changes)
Authors
Ivan Mitevski
(Columbia University New York, New York, United States)
Lorenzo M Polvani ORCID
(Columbia University New York, New York, United States)
Clara Orbe
(Goddard Institute for Space Studies New York, New York, United States)
Date Acquired
February 24, 2022
Publication Date
February 28, 2022
Publication Information
Publication: Geophysical Research Letters
Publisher: Wiley
Volume: 49
Issue: 5
Issue Publication Date: March 16, 2022
ISSN: 0094-8276
e-ISSN: 1944-8007
Subject Category
Meteorology And Climatology
Funding Number(s)
WBS: 509496.02.08.04.24
CONTRACT_GRANT: SAA-31389
Distribution Limits
Public
Copyright
Use by or on behalf of the US Gov. Permitted.
Technical Review
External Peer Committee
Keywords
climate sensitivity
forcing
feedbacks
asymmetry
No Preview Available