I think everyone would say that global warming stopped in those periods. The thing is that noone is suggesting that the warming around these periods was due to CO2. The last warming period has been attributed to this. The 3W/m2 is due to feedbacks and is actually a slowing of the radiation of heat from the atmosphere, not a warming from GHG - it is more like an insulating layer. The direct measurements and the last 10-15 years of little warming are potentially indicating that the forcings and feedbacks are lower than the 3W/m2.
