I clarify:
Let’s say scientists can’t come up with solutions to global problems, AI gets out of control and turns almost everyone into paperclips during wars, and in the 2040s or 2050s, the surviving people (about a few tens of millions around the world or even less) gradually return to the level of intelligence of their distant ancestors?
Well given the extinction of more than a half million essential crop species and the previously universal knowledge of farming that occurred in the last century. Expect to die alongside billions of others.