Yeah the worst thing is that with the extinction rate, he states that he implicitly sets the background extinction rate to 0 in the year 1000. This is going to bias his 3-point curve fitting even moreso.
The background extinction rate in the absence of humans is probably much higher than 0. New species are also continuously emerging while others are going extinct, so that the total number remains steady.
The background extinction rate in the absence of humans is probably much higher than 0. New species are also continuously emerging while others are going extinct, so that the total number remains steady.