On: US-Canada heatwave 'virtually impossible' without warming

[ghastmaster]

> If humans hadn't influenced the climate to the extent that they have, the event would have been 150 times less likely

A change in odds by a multiple of 150 does not equal "virtually impossible". Imagine 1/1000 vs 1/150,000 odds for a multimillion jackpot. Our weather and climate system is unfathomably complex. The odds that a compter model is correct is "virtually impossible".

[mjburgess → ghastmaster]

Indeed, one has to scale that probability by our confidence in the model itself -- so the probability itself has a wide confidence interval.

Ie., a more accurate claim is something like, `15x to 1500x`, with `150x` the best mean according to the model.

(Or even `1.5x to 15,000x` -- it would be useful to know).