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Observationally Constrained Cloud Phase Unmasks Orbitally Driven Climate Feedbacks
Author(s) -
Sagoo Navjit,
Storelvmo Trude,
Hahn Lily,
Tan Ivy,
Danco James,
Raney Bryan,
Broccoli Anthony J.
Publication year - 2021
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 - 10.1029/2020gl091873
Subject(s) - cloud feedback , climate model , environmental science , cloud computing , ice cloud , atmospheric sciences , climate state , climate change , climatology , geology , global warming , climate sensitivity , effects of global warming , computer science , oceanography , operating system
The mechanisms which amplify orbitally driven changes in insolation and drive the glacial cycles of the past 2.6 million years, the Pleistocene, are poorly understood. Previous studies indicate that cloud phase feedbacks oppose ice sheet initiation when orbital configuration supports ice sheet growth. Cloud phase was observationally constrained in a recent study and provides evidence for a weaker negative cloud feedback in response to carbon dioxide doubling. We observationally constrain cloud phase in the Community Earth System Model and explore how changes in orbital configuration impact the climate response. Constraining cloud phase weakens the negative high latitude cloud phase feedback and unmasks positive water vapor and cloud feedbacks (amount and optical depth) that extend cooling to lower latitudes. Snowfall accumulation and ablation metrics also support ice sheet expansion as seen in proxy records. This indicates that well‐known cloud and water vapor feedbacks are the mechanisms amplifying orbital climate forcing.