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Here Steve McIntyre tries to make sense of (and reconcile) the different "model vs observations" presentations with which we have all become too familiar. I think both AGW believers and skeptics will find this interesting.
[h=2]Reconciling Model-Observation Reconciliations[/h]Nov 18, 2017 – 3:38 PM
Two very different representations of consistency between models and observations are popularly circulated. On the one hand, John
Christy and Roy Spencer have frequently shown a graphic which purports to show a marked discrepancy between models and observations in tropical mid-troposphere, while, on the other hand, Zeke Hausfather, among others, have shown graphics which purport to show no 
discrepancy whatever between models and observations. I’ve commented on this topic on a number of occasions over the years, including two posts discussing AR5 graphics (here, here) with an update comparison in 2016 (here) and in 2017 (tweet).
There are several moving parts in such comparisons: troposphere or surface, tropical or global. Choice of reference period affects the rhetorical impression of time series plots. Boxplot comparisons of trends avoids this problem. I’ve presented such boxplots in the past and update for today’s post. . . . .
Conclusion
What does this all mean? Are models consistent with observations or not? Up to the recent very large El Nino, it seemed that even climate scientists were on the verge of conceding that models were running too hot, but the El Nino has given them a reprieve. After the very large 1998 El Nino, there was about 15 years of apparent “pause”. Will there be a similar pattern after the very large 2017 El Nino?
When one looks closely at the patterns as patterns, rather than to prove an argument, there are interesting inconsistencies between models and observations that do not necessarily show that the models are WRONG!!!, but neither are they very satisfying in proving that that the models are RIGHT!!!!
[h=2]Reconciling Model-Observation Reconciliations[/h]Nov 18, 2017 – 3:38 PM
Two very different representations of consistency between models and observations are popularly circulated. On the one hand, John
Christy and Roy Spencer have frequently shown a graphic which purports to show a marked discrepancy between models and observations in tropical mid-troposphere, while, on the other hand, Zeke Hausfather, among others, have shown graphics which purport to show no discrepancy whatever between models and observations. I’ve commented on this topic on a number of occasions over the years, including two posts discussing AR5 graphics (here, here) with an update comparison in 2016 (here) and in 2017 (tweet).There are several moving parts in such comparisons: troposphere or surface, tropical or global. Choice of reference period affects the rhetorical impression of time series plots. Boxplot comparisons of trends avoids this problem. I’ve presented such boxplots in the past and update for today’s post. . . . .
Conclusion
What does this all mean? Are models consistent with observations or not? Up to the recent very large El Nino, it seemed that even climate scientists were on the verge of conceding that models were running too hot, but the El Nino has given them a reprieve. After the very large 1998 El Nino, there was about 15 years of apparent “pause”. Will there be a similar pattern after the very large 2017 El Nino?
When one looks closely at the patterns as patterns, rather than to prove an argument, there are interesting inconsistencies between models and observations that do not necessarily show that the models are WRONG!!!, but neither are they very satisfying in proving that that the models are RIGHT!!!!
- According to models, tropospheric trends should be greater than surface trends. This is true over ocean, but not over land. Does this indicate that the surface series over land may have baked in non-climatic factors, as commonly argued by “skeptics”, such that the increase, while real, is exaggerated?
- According to models, marine air temperature trends should be greater than SST trends, but the opposite is the case. Does this indicate that SST series may have baked in some non-climatic factors, such that the increase, while real, is exaggerated?
