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Maximum entropy production, cloud feedback, and climate change
Author(s) -
Paltridge Garth W.,
Farquhar Graham D.,
Cuntz Matthias
Publication year - 2007
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 - 10.1029/2007gl029925
Subject(s) - equator , environmental science , cloud albedo , cloud feedback , atmospheric sciences , latitude , water vapor , lapse rate , albedo (alchemy) , cloud computing , entropy production , climate change , climatology , cloud cover , climate sensitivity , climate model , meteorology , physics , geology , thermodynamics , computer science , art , oceanography , astronomy , performance art , art history , operating system
A steady‐state energy‐balance climate model based on a global constraint of maximum entropy production is used to examine cloud feedback and the response of surface temperature T to doubled atmospheric CO 2 . The constraint ensures that change in zonal cloud amount θ necessarily involves change in the convergence KX of meridional energy flow. Without other feedbacks, the changes in θ, KX and T range from about 2%, 2 Wm −2 and 1.5 K respectively at the equator to −2%, −2 Wm −2 and 0.5 K at the poles. Global‐average cloud effectively remains unchanged with increasing CO 2 and has little effect on global‐average temperature. Global‐average cloud decreases with increasing water vapour and amplifies the positive feedback of water vapour and lapse rate. The net result is less cloud at all latitudes and a rise in T of the order of 3 K at the equator and 1 K at the poles. Ice‐albedo and solar absorption feedbacks are not considered.