I don’t think that (delayed weather effects of the fires) would be “major”, but I’d not rule such completely.
OTOH, one has to consider that in this event we are looking at under 5% of the Earth’s surface setting record cold temperatures, in a mere eyeblink in time (of records).
I’d also point out that your volcano reference reminds me of something — a mistake FReepers often make. While I tend to believe human CO2 emissions are more likely to delay or keep us out of another period of glaciation, than do some sort of human species threatening harm, humans and their enterprises in total actually DO exceed total volcanic releases of CO2, on an annual basis. Now if Yellowstone goes off, full tilt, that might not be true, but then CO2 may be the least of the problems: For one thing, the cooling effect of the particulates blasted into the atmosphere likely exceeds the effect of the CO2 released.
However, back to my point(!), in normal years / times, using current figures as the basis of calculation (such as how much CO2 is produced by burning a gallon of gasoline), some junior / senior high school level math, compared with what volcanologists have known for some time about volcanic releases, will easily show that the TOTAL of human CO2 releases exceeds that of volcanos in even fairly active years, by quite a bit. Volcanoes are big, but there are a LOT of us.
Of course, even humans are but a small part of the picture. Humans and our activities are only a small portion of the chemical and biochemical activity on Earth.
Although it draws some dubious conclusions, and other dubious interpretations can be made from the data, this article creates a fascinating “visual” of the scale of “life” on Earth, compared to humans:
thank you for your answer and the link very interesting information.