Global civilization is intimately interconnected. Any serious upset would wipe out the industries most dependent upon it. The first to go would be everything hi

Global civilization is intimately interconnected. Any serious upset would wipe out the industries most dependent upon it. The first to go would be everything high-tech -- chips, aircraft, cars. New car manufacturies like in the 20th century might be got up from the scraps. But mass starvation would ensue, leading to huge wars that probably would quickly turn nuclear. The most likely proximate causes of collapse would be ocean ecosystem collapse caused by acidification, eliminating the current protein source billions of people depend on, or mass migration from newly uninhabitable areas. We see hints of both already.