The eruption lasted perhaps two weeks, but the ensuing "volcanic winter" resulted in a decrease in average global temperatures by 3 to 3.5 degrees Celsius for several years. Greenland ice cores record a pulse of starkly reduced levels of organic carbon sequestration. Very few plants or animals in southeast Asia would have survived, and it is possible that the eruption caused a planet-wide die-off.
[ame=http://en.wikipedia.org/wiki/Lake_Toba]Lake Toba - Wikipedia, the free encyclopedia[/ame]
The Toba eruprion is the one that pushed humans to the brink of extinction (some estimate as few as 14,000 humans were left before things got back to normal).
I would say those are pretty major.
So tell me, can you give some documentation of a volcano warming the Earth? Because you agree with something I said in sarcasm, and I have never seen anything to show that warming occurs after a volcano eruption.