Good roundup and fair estimate, from the limited guesses. I have read bits from many of these authors. You left out Ugo Bardi, who has produced some strong evidence of a common model pattern of systems collapse in all sorts of widely varying types of systems at many different scales. “Seneca collapse” Books and articles of same name. Collapse is a feature, not a bug. It is more than likely to be rapid, because of our previous exponential growth and highly intertwined global trade systems, and dependence on over-exploited biosphere. This Biosphere is the mother of all our systems, and it is also prone to collapse. With global warming now average of 0.25 – 0.3 C per decade , be assured that this global systems collapse is going to be a big and long one, and the collapse of civilisation will happen at an early stage. I predict more collapsing states will be obvious from 2025, and some are obvious now.