Geologists. And the answer is "none" for the past 25 or so millenia, and "one" since Toba.
Also, unless you've had supervolcanoes go off in your bedroom and didn't tell anybody, the evidence for human impact is exceedingly clear.
Geologists might know, same as astronomers might know what Black Holes and Pulsars really are.
On the other hand, it is a geologist's call to search for answers and for truth. Saying that they truly know is the same as saying nothing.
Geologists. And the answer is "none" for the past 25 or so millenia, and "one" since Toba.
Also, unless you've had supervolcanoes go off in your bedroom and didn't tell anybody, the evidence for human impact is exceedingly clear.