[throwawaysea]

Maybe this is just a semantic debate, but I (and likely most people) interpret the phrase “existential threat” in the context of climate change as referring to humans. As in, humanity/civilization will not survive the predicted climate changes. However, the worst case scenarios are not extinction of humans but rather death in the millions to hundreds of millions, assuming we don’t adapt in various ways.

[3gg]

Well, for all those hundreds of millions it will indeed be existential (and I have read that a 4C Earth could only be able to host ~1 billion people, so the deaths could be a lot more than "millions to hundreds of millions".) In any case, arguing about the technicalities of the word "existential" at this point denotes such a complete lack of empathy that it's not even worth it.

[edgyquant]

Even the deaths of hundreds of millions requires a number of worst case scenarios to happen, which isn’t all that likely.