This kind of Question might be unpopular but do those wildfires have any quantitative relevance in accelerating global warming?
Or ask differently how much of Siberia would have to burn to make any noticeable difference In the CO2 balance
However it wouldn't take much in the grand scheme of things to negate any reductions in CO2 release we manage to make as a civilization, more or less maintaining the total current CO2 release levels indefinitely. That's a pretty worrying scenario by itself.
That decomposition not only produces carbon dioxide but also methane and methane is a much worse greenhouse gas than carbon dioxide.
So yes, this thawing permafrost provides several ways to help accelerate global warming.