Actually, volcanos typically emit cooling gasses (mainly SO2) and particulates (block sunlight) that override the effects of greenhouse gases emitted. So, if a mega-eruption occurs, cooling occurs. Our efforts to reduce AWG might backfire...
https://en.wikipedia.org/wiki/1815_eruption_of_Mount_Tambora#Disruption_of_global_temperatures
https://en.wikipedia.org/wiki/Krakatoa#1883_eruption
That was my point, though poorly said