Or The Samalas eruption - which is believed to have caused the Little Ice Age - and killed 90% of Europeans & North Americans at the time (55M people).
I imagine many millions of large mammals and birds and insects also died.
> In a 2012 paper, Miller et al. link the Little Ice Age to an "unusual 50-year-long episode with four large sulfur-rich explosive eruptions, each with global sulfate loading >60 Tg" and notes that "large changes in solar irradiance are not required."[8]
> The elimination of nearly 55 million, or 90 per cent, of Indigenous people in the Americas during European colonization led to global climate change and the “Little Ice Age” of the 17th century, a recent study finds.
In fairness, the Samalas Eruption did not directly lead to Ghengis Khan or Black Death. But during the Little Ice Age - the populations reduced by ~90%.
I imagine many millions of large mammals and birds and insects also died.