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Why are climate models reproducing the observed global surface warming so well?
Author(s) -
Knutti Reto
Publication year - 2008
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 - 10.1029/2008gl034932
Subject(s) - radiative forcing , climate sensitivity , spurious relationship , climate model , climatology , forcing (mathematics) , environmental science , climate change , atmospheric sciences , global warming , aerosol , range (aeronautics) , radiative transfer , meteorology , geology , physics , mathematics , oceanography , statistics , materials science , composite material , quantum mechanics
Climate models reproduce the observed surface warming better than one would expect given the uncertainties in radiative forcing, climate sensitivity and ocean heat uptake, suggesting that different models show similar warming for different reasons. It is shown that while climate sensitivity and radiative forcing are indeed correlated across the latest ensemble of models, eliminating this correlation would not strongly change the uncertainty range of long‐term temperature projections. However, since most models do not incorporate the aerosol indirect effects, model agreement with observations may be partly spurious. The incorporation of more detailed aerosol effects in future models could lead to inconsistencies between simulated and observed past warming, unless the effects are small or compensated by additional forcings. It is argued that parameter correlations across models are neither unexpected nor problematic if the models are interpreted as conditional on observations.