The influence of anthropogenic aerosol on multi-decadal variations of historical global climate
Wilcox, L.J., Highwood, E.J. and Dunstone, N.J. (2013) The influence of anthropogenic aerosol on multi-decadal variations of historical global climate. Environmental Research Letters, 8 (2). 024033. ISSN 1748-9326
To link to this item DOI: 10.1088/1748-9326/8/2/024033
Analysis of single forcing runs from CMIP5 (the fifth Coupled Model Intercomparison Project) simulations shows that the mid-twentieth century temperature hiatus, and the coincident decrease in precipitation, is likely to have been influenced strongly by anthropogenic aerosol forcing. Models that include a representation of the indirect effect of aerosol better reproduce inter-decadal variability in historical global-mean near-surface temperatures, particularly the cooling in the 1950s and 1960s, compared to models with representation of the aerosol direct effect only. Models with the indirect effect also show a more pronounced decrease in precipitation during this period, which is in better agreement with observations, and greater inter-decadal variability in the inter-hemispheric temperature difference. This study demonstrates the importance of representing aerosols, and their indirect effects, in general circulation models, and suggests that inter-model diversity in aerosol burden and representation of aerosol–cloud interaction can produce substantial variation in simulations of climate variability on multi decadal timescales.