You’re probably right. Collapse of our industrial and big agricultural infrastructures and global market economy due to accelerating global heating (no more of this euphemistic “climate change” nonsense) is now inevitable, and the consequences will be horrifying. But extinction? I doubt it. We are an incredibly resilient species. While there will no doubt be a massive die-off, starting with the overheated tropics, I strongly doubt that we will all perish.
The question becomes, how can we best improve our chances of survival? My guess is that there will be two broad categories of survivors: (1) ruthless warlords and their gangs of resilient thugs, fighting over land and food; and (2) Gaians, who organize themselves into contiguous villages, practicing permaculture and following injunctions like this: “Grow Gardens, Grow Community, Grow Awareness by Learning, Teaching, Healing, and Creating.” (Read Octavia Butler’s “Parable of the Sower” for an idea of how this might work in a violent, apocalyptic landscape.)