Had a brief look at the actuary report, and the 4 billion figure comes right at the top of the table for most 'extreme' possible 'risk impact'.
https://actuaries.org.uk/media/ni4erlna/planetary-solvency.pdf
Hallam says:
'I take the insurance industry's figure at face value: a
prediction, buried in an appendix, describing at least four billion deaths at 3°C of warming.' -
https://rogerhallam.com/the-insurance-industry-predicts-mass-death-what-do-we-do-about-it/ But right before the appendix table, and even included in the screenshot he provides is this caveat:
'The table below shows the Planetary Solvency risk impact and likelihood matrix utilised for the illustrative Planetary Solvency outputs contained in previous sections. A risk impact matrix is a methodology for ranking potential impacts, not a prediction or central scenario.' (p.32 of the report)
I skimmed the rest of the report to see if they explained how they got this number or provide a link to a scientific paper pointing in that direction, but no, it seems they pulled it out of the air (being charitable). I don't see why we should accept at face value the pontifications of ppl in insurance who have minimal understanding of climate science or any of the other disciplines that *might* give weight to pronouncements about the future, even if only theoretical.
Hallam wants to emphasise morality and urge a response based on that. Fine, but don't lie to people to get the response you want. That's manipulative and counterproductive when you get found out.
jeers,
I