Well, in 1783-1784, Iceland saw the Laki eruptions which emitted dozens of megatons of material into the upper atmosphere over a period of 8 months. This impacted many parts of the world and caused extreme weather. The end result was a decade of extreme, deteriorated weather with failed crops and hunger across much of Europe and North America. It is theorized that the eruption was an indirect driver for the French Revolution.
[1] https://www.forbes.com/sites/davidbressan/2015/06/08/this-17...
[2] https://www.wired.com/2013/06/local-and-global-impacts-1793-...