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I'm not suggesting to assume the IPCC is wrong - but that the reports have a conservative outlook. In some respects that's a good thing in that outlying and unclear studies and predictions will be omitted, yet some of those outliers may turn out to be accurate and the middle of the road view wrong. That's fine and expected, if frustrating at times. In other respects, notably the structure of having a political approval stage for reports has, if that Guardian Saudi piece is to be believed, subsequently toned down those consensus views -- under pressure from home for political or economic reasons. There's also an awful lot of "he said, she said", meaning it's impossible to reach certainty from those reports. Without criticising any nation's scientific and economic representatives involved in the preparation phase, there are multiple representatives criticising that final political approval phase... Draw your own conclusions. The upshot for those of us trying to make sense of it is IPCC tends to a very diligent presentation of the least contentious, which subsequent measurements have shown to have underestimated it on multiple occasions. Which leaves me thinking IPCC reports a best-case scenario: I believe them, it's the best consensus we have, but am not surprised if something crops up that turns out to be worse or more significant than projected. I still find that far better than had they been over-estimating impacts consistently. YMMV. :) Specifically on tipping points, they're likely to always be something of an unknown before they actually tip. Once a threshold has been passed and an ice sheet thought safe for decades collapses, or permafrost tips into catastrophic melting it's clear the threshold was passed, and we know from hindsight. Predicting and modelling on the other hand will probably remain near impossible - we only really know after it's switched. Which is, of course, after it's too late and tipping them back effectively impossible. That said, that old Scientific American article mentioned they would be including some consideration to threats from tipping points and non-linear effects from 2014. |