The_Barnacle wrote on Apr 29
th, 2017 at 1:56pm:
So what did AR4 say, it is the reference for the quote?
"and the possibility that the response to solar forcing could be underestimated by climate models." - oh models
"However, estimates of some radiative forcings remain uncertain, including aerosol forcing and inter-decadal variations in solar forcing. " - hmmm - uncertainties.
http://www.ipcc.ch/publications_and_data/ar4/wg1/en/ch9s9-es.htmlExecutive summary
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Some external influences, such as changes in solar radiation and volcanism, occur naturally and contribute to the total natural variability of the climate system."
http://www.ipcc.ch/publications_and_data/ar4/wg1/en/ch9s9-1.html#9-1-1"The effects of forcing uncertainties, which can be considerable for some forcing agents such as solar and aerosol forcing (Section 9.2), also remain difficult to evaluate despite advances in research. "
" Uncertainties in external forcing were also reported, particularly in anthropogenic aerosol, solar and volcanic forcing, and in the magnitude of the corresponding climate responses. These uncertainties contributed to uncertainties in detection and attribution studies. Particularly, estimates of the contribution to the 20th-century warming by natural forcings and anthropogenic forcings other than greenhouse gases showed some discrepancies with climate simulations
and were model dependent. "
http://www.ipcc.ch/publications_and_data/ar4/wg1/en/ch9s9-1-3.They don't seem all that sure.