The worst case scenario is still a mass extinction event unlike anything witnessed by the human species, plus global food and water shortages, and certain areas of the world becoming unsuitable for human life during the hot months.

That means mass migration and conflict over resources, and a deteriorating ecosystem that we still very much rely on to produce food and healthy living conditions.

https://www.vox.com/22620706/climate-change-ipcc-report-2021...

Basically, scenario 4 or 5 outlined in that article is what I see happening. Sure, it's not a guaranteed extinction, but it will devastating, and it's far more likely than a GAI takeover.