>it's extinction of the civilization. For a civilization to be detectable it has to be at least at our level,
My point is that we won't go extinct, we'll bounce back and get another try.
>especially if we've extracted all the easy to extract natural resources making
Would you rather hollow out a mountain to mine minerals or dredge through what used to be a major city? We've concentrated all sorts of useful things on earth's surface. If anything the next civilization will have it easy.
>harder for our ancestors to rev back up, or if large parts of the planet become uninhabitable.
Large parts of the planet were more or less uninhabitable. The few people who lived in the arctic and the deserts mostly just followed food/water sources. They contributed little to civilization's progress (mostly in the field of astronomy because desert nights and polar winters give you plenty of time to look at the starts) because they didn't have the spare resources to engage in those pursuits because they were too busy surviving. Progress has always come from the places that are easy to live in and therefore have resource surpluses.