I'd say human contributed greenhouse gas emissions are the main limiting factor for the earth's carrying capacity for human lives. We're already experiencing many more severe climate related weather events and the problem is only going to get worse each year.
We do, but they only contribute a small portion of the world's energy. It will take a long time to get to a point where most energy generated is renewable, and by that point, the climate is going to be a much much bigger problem.
That's a big problem for the next several decades, but by the time longevity tech is mature enough to significantly affect populations, either we'll have converted to non-carbon energy or longevity tech will be pretty much irrelevant anyway.
Right, but I didn't mean humans would be extinct necessarily, just that longevity tech would be mostly irrelevant to population counts. In a lot of those scenarios, the main causes of death are likely to be things like starvation, disease, or accidents, rather than old age.
Admittedly this isn't true of all possible scenarios. And in some, longevity would be really helpful.
