Heaven and Hell (on Earth)

Christina Figueres has written a book 'This is the decade and we are the generation' in which she outlines the most optimistic (https://www.theguardian.com/environment/2020/feb/15/best-case-scenario-2050-climate-crisis-future-we-choose-christiana-figueres-tom-rivett-carnac) and most pessimistic (https://www.theguardian.com/environment/2020/feb/15/worst-case-scenario-2050-climate-crisis-future-we-choose-christiana-figueres-tom-rivett-carnac) outcomes for the year 2050. In the former, greenhouse gases have been rigorously controlled and the increase in global temperature limited to the Paris-agreed 1.5 degrees C. In the latter, the climate altering gases (and particulates) have continued to rise unchecked and the global temperature is more than 3 degrees C higher and rising. It's pretty clear which is the preferable scenario but very unclear which will actually prevail.