Preparing For the Climate Endgame?

A paper by a group of climate scientists in Proceedings of the National Academy of Sciences, claims the risk of planetary societal collapse and, even human extinction, have been 'dangerously underexplored' (https://www.theguardian.com/environment/2022/aug/01/climate-endgame-risk-human-extinction-scientists-global-heating-catastrophe). These climate scientists point out that climate change has played a major role in every planetary mass extinction event. Climate change has also been a factor in the collapse of several formerly thriving human societies. We hear a lot about the imperative to limit global heating to 1.5 degrees Centigrade above pre-Industrial levels (it's already 1.1)! Current 'greenhouse gas' emissions will, however, by 2100, produce a rise of 2.1-3.9 degrees. Even if all the set long-term targets are enforced (a very big 'if'!), the rise will still be 1.7-2.6 degrees by the next century. The authors of this paper say that we need to evaluate the consequences of global heating beyond 3 degrees Centigrade. They hope there is only a small chance of this 'climate endgame'. They believe, however, that the uncertainties of future 'greenhouse gas' emissions and the climate system, means that 'cataclysmic scenarios' can't be ruled out. Climate change has complex effects. These climate scientists feel there is an urgent need for research agendas examining the interplay between famine, extreme weather, war and disease. It does seem that many climate scientists are getting less reluctant to 'press the panic button'. That must say something about the perceived level of risk!