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To what extent can interannual CO 2 variability constrain carbon cycle sensitivity to climate change in CMIP5 Earth System Models?
Author(s) -
Wang Jun,
Zeng Ning,
Liu Yimin,
Bao Qing
Publication year - 2014
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 - 10.1002/2014gl060004
Subject(s) - coupled model intercomparison project , earth system science , carbon cycle , climate change , environmental science , climatology , climate sensitivity , sensitivity (control systems) , carbon fibers , atmospheric sciences , greenhouse gas , climate model , global change , ecosystem , geology , ecology , mathematics , oceanography , algorithm , electronic engineering , composite number , engineering , biology
We analyze the carbon‐climate feedback in eight Earth System Models from phase 5 of the Coupled Model Intercomparison Project (CMIP5). We focus on tropical land carbon change and find decreases (−31.02 to −169.32 GtC K −1 ) indicating tropical ecosystems will release carbon as temperature warms, thus contributing to a positive feedback identified in earlier studies. We further investigate the relationship between tropical land carbon change and sensitivity of historical atmospheric CO 2 growth rate to tropical temperature variability and find a weak linear relationship. This sensitivity for most models is stronger than observed. We further use this “emergent constraint” to constrain uncertainties in model‐projected future carbon‐climate changes and find little effect in narrowing the model spread, but the mean sensitivity is slightly smaller. This contrasts with earlier Coupled Carbon Cycle Climate Model Intercomparison Project results, highlighting the challenge in constraining future projections by modern observations and the necessity for evaluating such relationships continuously.