[thejohnconway]

> That is just a mathematical truism.

No it isn’t. Diversity rates have risen and fallen over the history of life, and it can take many millions of years for life to re-diversify after a mass extinction event (like the one we are causing now). Evolution by natural selection is not rapid when it comes to larger organisms.

[roenxi]

During that time the number of new species will be approximately equal to the number dying out though. Otherwise the re-population would be rapid. The reason it takes millions of years in that case is because the two rates generally pretty similar. It is quite hard to get the two rates to stay far apart for any length of time. It is a truism that they match and they're going to return to matching whatever humans do. And them matching doesn't mean that the number of species isn't drifting radically over time.

I get that thejohnconway probably didn't literally mean it when he said "Species usually go extinct at a rate at which new diversity can take their place" in the sense of it always being true no matter how many species there are - but one of the major issues with the global warming debate is it is actually pretty hard to articulate what the problem is with a lot of species going extinct if people don't use vague language like that which sounds bad but doesn't actually have much of a point to it. People will generally not notice. Nobody notices all the things that have already gone extinct. The world will just be what they are used to for most people. Most species are threats, nuisances or domesticated and as safe as humans are.

[thejohnconway]

Species is a concept that isn't particularly well defined, and certainly not in palaeontology. One can see, however, diverging body plans (disparity), distinct lineages (diversity). If we take our extinction further, it will probably be tens of millions of years before we see the kind of diversity and disparity we had until the last couple of centuries. Its the period of imbalance that causes the problem.

Anyway, congrats on not caring about nature. It's must feel very free.