Extract from G Dedrick Robinson's book:
Maybe they [IPCC] didn't think it mattered enough to policy makers to waste their time on them [errors]. The important thing is the graph projecting warming, isn't that so? That makes the danger clear.
Yes, the graph certainly does that, but only if one does not understand the importance of the errors. Consider just one of the uncertainties, the 25 W/m² in shortwave radiation reflected into space. As mentioned in chapter Five, 1.6 W/m² is the total estimated positive radiative forcing for all anthropogenic greenhouse gas emissions.12 Now consider that the uncertainty from just one physical parameter is more than 15 times that. There are similar uncertainties for outgoing longwave radiation and surface heat flux. How then, can someone claim to predict something such as warming, if the error involved in the procedure is more than 15 times greater than the effect one is trying to predict? Another imponderable is why the IPCC puts a graph in their only short, easy-to-read and hard hitting publication, the Report for Policymakers, that contains a graph labeled with one standard deviation error, when the uncertainties in the GCMs are greater than the effects they're claiming to predict.
page 85, G Dedrick Robinson (PhD) "Global Warming, Alarmists, Skeptics and Deniers: A geologist looks at the science of climate change"