[roenxi]

> Species usually go extinct at a rate at which new diversity can take their place.

That is just a mathematical truism. If all species died tomorrow and only humans were left we'd still hit an equilibrium where species were going extinct at the same rate new ones were appearing. The system moves quickly to an equilibrium where usually extinctions = new species.

In practice ecosystems collapse fairly regularly. This stuff isn't planned and nature is messy. Every time something changes ecosystems might collapse.

> Billions of people have died in the past, but it would obviously be a catastrophic tragedy if billions of people died this year.

Sure. Most people would make a show of moral objection to that. But if we look at what the humans actually do - they typically kill everything in sight that is larger than dog, concrete over what is left and poison any insects that made it through the slaughter. I dunno if anyone is tracking how many species we've wiped out on the road to apex predator, but there are going to be quite a few already. Cities are great for humans and not much else. In fact, we purposefully cause ecosystem collapses because it suits us.

That argument is only going to get pushback from very argumentative people but it is actually unpersuasive in practice. A billion human deaths is a tragedy but extinct species seems like it would be acceptable for bettering the material comfort of humans. Humans have generally accepted that trade in the past and we're still purposefully trying to ... I dunno, specie-cide a few that we don't like.

[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.

[roenxi]

The average person lives in a city where they don't interact with nature, aren't near nature and aren't particularly affected by nature. People aren't argumentative about it but their choices suggest that on balance, the normal response is not to care. There are more important things to worry about like the well-being of humans.

[xboxnolifes]

If all species besides humans went extinct tomorrow, humans would also quickly go extinct. The equilibrium would be 0 extinctions and 0 new species.

Maybe millions or billions of years years later that would increase to >0, but i think its fair to call that a total collapse of all life on Earth for those interim years.