Thank you for this work - how unlikely is a scenario counted as in this analysis before it's excluded as implausible, and what light could the work shed on more likely but still very serious risks (taking into account limitations of climate models because of, for example, clouds)?

If there was a 1% chance of the ending of general habitability of our planet I'd be calling it out as 'very risky', unacceptable. You would not fly or drive with that level of risk. We are in fifty (50x) times riskier territory.