Volcanic eruptions can have abrupt local impacts but they can have episodic global climate impacts that can give rise to geopolitical instabilities and migrations.
"Roughly 1,500 volcanoes are potentially active right now, meaning that they’ve erupted at some point in the last 10,000 years." "Right now, roughly a dozen volcanoes are erupting. In all likelihood, they're nothing to worry about — it's doubtful you’ve even heard of them. But every once in a while, there's bound to be a really big eruption. How its effects ripple around the world awaits to be seen." Source
Sulfate is a major atmospheric pollutant and radiative forcing (RF) factor that influences air quality, cloud microphysics, and climate. One of the principal vehicles by which volcanoes can alter climate is the release of great quantities of sulfates and dust which can have a regional and global cooling effect. Sulfate is given off by industry (burning coal and oil) as well as through some volcanic eruptions. Sulphate concentrations in the atmosphere have risen with industrialization acting to mask the warming impact of other gases.
