And I'm not making any predictions, just observations. This might come down to semantics on what exactly you suppose sustainable to mean or whether or not it is desirable, but causing an ongoing mass extinction event does not meet my definition of sustainable.
I'm talking about environmental sustainability to be clear (hopefully it was from the context but I may not have been explicit enough). I don't doubt we could physically feed billions more people at least as long as we have cheap energy and fertilizers from fossil fuels if we accepted ever increasing environmental destruction.
Claiming we are in the middle of a mass extinction event is a prediction, not an observation. It will become an observation when you have actually seen billions of species disappear over time. You don't extrapolate an extinction based on trends over dozens of years (especially on mostly imperfect data).
because you are wrong. 100 years ago people said we would all starve when the world population reaches 1 billion people. then we not only not starved but became wealthier as well. Doom predictions are mostly damn wrong.