text: Moreover, the best estimate the IPCC gives in AR5 for total aerosol forcing is not fully based on observations. It is an expert judgement based on a composite of estimates derived from simulations by global climate models and from satellite observations. The nine satellite-observation-derived aerosol forcing estimates featured in Figure 7.19 of AR5 WGI range from 0.09 W/m 2 to 0.95 W/m 2 , with a mean of 0.65 W/m 2 . Of these, six satellite studies with a mean best estimate of 0.78 W/m 2 were taken into account in deciding on the 0.9 W/m 2 AR5 composite best estimate of total aerosol forcing.