Well that turned out to be pretty straightforward. Although this stuff always takes time.
jopo has been telling us about the polar vortex, and specifically how - in his interpretation - the polar vortex and the (presumably northern polar) jet stream has been moving north. And he has been arguing how that contradicts the study I posted from Jenifer Francis at Rutgers Uni on the increasing wobbliness of the northern polar jet stream and the possibility this is related to warming.
And jopo has been trying to suggest that, in posting on Francis' studies, that I am contradicting the IPCC.
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So I've said I'd look at that in more detail.
The reference content jopo embeds in his post is from 7.2.4.1 of the IPCC AR5. And it refers to 2.7.4 and 2.7.5, regarding shifting jet streams.
It turns out those sections are talking about observations - NOT predictions. So there are no IPCC reported modelling predictions on this. Either that I am aware of, nor in jopo's reference.
It also turns out that the primary observations from 2.74 and 2.75 are about movement of the TROPICAL jet streams, not the polar vortex or polar jet stream.
The only stuff I can find on the northern polar vortex is at 2.7.7 and is pretty equivocal, stating "trends in the Northern Polar Vortex wereconsidered uncertain owing to its large variability."
That's all reporting on observations up to sometime before the AR4 publication in 2013.
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All that is, I believe consistent with what I have been saying, That modelling of the polar vortex and polar jet stream effects is problematic as the model resolution hasn't been sufficient to date to deliver clarity on that.
And now we also find from jopo's reference that even the observations indicate any polar jet stream trends are uncertain.
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As far as I can tell then the work Jennifer Francis has been doing is leading edge, attempting to understand what may have caused that recent (last five years or so) obvious observed polar vortex wobbliness. And while she has a theory that this may relate to warming, due to the reducing differential between the poles and equator, she acknowledges there is more work to do to provide conclusive evidence.
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Sorry jopo, but as far as I can see, not only is your thread a storm in a tea cup, but the actual evidence of your own reference doesn't support what you are arguing, and primarily is about the tropical jet streams.
You owe me a beer for wasting my time on yet another denial furphy.
