[wildmanxx]

You are kinda arguing against your point.

Around the year 1000, it's a reasonable guess to assume that emergence of new species and species extinction were roughly in balance, so net extinction rate was indeed around 0.

Today, it's well-established that this net extinction rate is as horrible as is described. A few new species emerging here and there are not enough to compensate for the mess that we are causing on the extinction front, by orders of magnitude.

[m_dupont]

I might have not expressed myself well in the previous comment, but when I say that "New species are also continuously emerging", it is to prove that the background extinction rate is not zero, not that we don't have a problem.

The curve that he fitted is not the net extinction rate. It's simply the total number of extinctions.

The graph he plots shows the total number of extinctions at year 1000 being 0 or almost 0. This is an assumption. In the absence of humans the extinction rate could be 1,2,10 per year, whatever, it's some small number. The point is that when you are fitting an exponential curve to 3 data points, the resulting curve will be very sensitive to small changes in the value of that point at year 1000. In particular, choosing a value of 0 will force the model towards the steepest possible gradient that the model can allow. i.e. it's biased towards alarmism.

EDIT: Although, when I think about it a little more, a reasonable model would model the extinction rate as an exponential plus a constant value, which would change things. Though a reasonable model probably wouldn't assume an exponential model at all based on 2 data points

[sidewndr46]

Simply looking at the net species over a year doesn't really tell the full story of it.

You can lose megafauna like the American Bison or Steller's sea cow. Smaller fauna like the thylacine are also lost. Such species aren't going to re-emerge in the timescale of humanity. What I named off are just 3 species. If 3 species of ants happen to replace them, that's not really making up the difference. The world has plenty of ants in plenty of species already.

Also please don't drag out the "American Bison isn't extinct!" argument. There were less than a thousand at some point in the 19th century, so all the genetic diversity they had is gone. They've been bred with cattle to the point that the remaining herds are basically all hybrids, despite claims to the contrary. They're also functionally extinct in North America, as all herds are dependent on management at this point.

[jimbokun]

> Around the year 1000, it's a reasonable guess to assume that emergence of new species and species extinction were roughly in balance

Why?