This is the most relevant case for comparison with observational estimates, as the effect of individual forcings can not be observed in the latter. (climateaudit.org)
Results from key studies on observational estimates of ECS (in °C) from instrumental data, individual volcanic eruptions, data for the last millennium, and simulations of the LGM. (ipcc.ch)
are actually for RFari, but that equals the purely observational estimate for AFari (− 0.4 W / m ² in 2011), so they can stand. (bishop-hill.net)