[Aktungbby]

https://www.popularmechanics.com/science/animals/a34968104/mass-extinctions-happen-every-27-million-years/

Scientists have new evidence that Earth’s many periodic mass extinctions follow a cycle of about 27 million years, connecting the five major mass extinctions with more minor ones occurring throughout Earth’s life-fostering timespan. The artificial intelligence analysis could also shift how evolutionary scientists think about the aftermath of mass extinctions....To study these events, the scientists fed more than a million data points about 170,000-plus species into a machine learning algorithm that processed all of it into one giant statistical timeline. From that information, the algorithm concluded that while the “big five” mass extinctions are part of the top 5 percent of all time population change events, so are “seven additional mass extinctions, two combined mass extinction–radiation events and 15 mass radiations.” ...Too many of a particular species almost always ends up harming the surroundings, even dramatically. Like we said: it's complicated.

My bet's on a mass radiation event from 8,000,000,000, too many of a particular species prone to "harming the surroundings"; in a whole lot less than 27,OOO,OOO years!!??