David L. Hagen | March 8, 2013 at 9:44 am |
1) Did the Met Office say that the model mean temperature not greater than zero for 15 years (at 95% level)?
There is nothing in the construction of GCMs that constrains any future span’s trend to the specific years in which the span occurs. How could it?
Over the course of all the GCM runs conventionally referred to as the IPCC ensemble forecast, there were falling 15 year trends.
OR the global temperature trend is less than zero (at the 95% level)?
So we see that even if the global temperature trend were less than zero, that is perfectly consonant with the model projections.
2) Was the fifteen year global temperature trend from 1940 to 1975 significantly greater than zero?
As 1940 to 1975 is longer than 15 years, the answer is both:
http://www.woodfortrees.org/plot/gistemp/mean:89/mean:91/from:1940/plot/gistemp/mean:89/mean:91/derivative/normalise/from:1940/plot/gistemp/mean:29/mean:31/scale:0.00001/from:1940/plot/gistemp/mean:29/mean:31/from:1940/plot/gistemp/mean:29/mean:31/derivative/normalise/from:1940/plot/gistemp/last:180/trend/plot/esrl-co2/mean:11/mean:13/normalise
3) Can you quantitatively show that the GCM’s mean temperature predictions are more accurate than Scafetta’s 2000 predictions?
Why limit ourselves to Scafetta?
Why not include other astrologers, people who read the innards of pigeons and goats, dowsers, and random writers of science fiction? There’s bound to be a few who based on some fabulistic standard were spot-on in their predictions.
4) Tthe GCM global temperature model means able to forecast/hindcast half of historical tempreatures given data from the other half of the period?
This focus on temperature level, this mania for holding models to an impossible standard, where does it come from? Do that many people have childhood trauma associated with thermometers?
Temperature level is not a valid metric of success for a GCM. Trend profile is. And yes, GCMs are validated against that metric.
5) If not, why rely on the less accurate models?
Here’s where we come to the advantage of actual scientific hypothesis over fingoism. With a clear understanding of the mechanism proposed in the model, the proponents can identify how accurate the models ought be, and especially how accurate they ought not be.
Scafetta’s produced a mystery-based voodoo fiction that is highly accurate, but not very convincing.
6) On what statistical basis do you evaluate when GCM’s do/do not predict global temperature?
Why waste time generating statistics measuring impossible success? GCMs can’t predict volcanic eruptions; until something can, there’s no way to predict global temperature level, regardless of the alignment of the planets or how accurate Scafetta’s horoscope appears for a brief moment if you squint favorably.
7) On what statistical basis do you judge that GCM’s are able to distinguish:
7.1) major anthropogenic warming from
7.2) minor anthropogenic warming from
7.3) the null hypothesis of natural change?
And why distinguish 7,.1 from 7.2? A trespass is a trespass whether it’s a toe or the whole hind end. There’s no difference to most of us whether someone peed into the well, ‘but only a little’, as to whether or not there’s an offense.
For 7.3, the profile of temperature trends with and without CO2 forcing is dramatically different in the model runs. 100% is a pretty compelling statistic.
My eyeball comparison says the GCM’s are running way hotter than actual temperature.
Each of the IPCC’s last 4 temperature predictions trend much hotter than subsequent global temperature reality.
To me that evidences systemic Type B error.
Or, evidence you’ve systematically applied the wrong metric of success?
8) How do you quantify the presence/absence of such systemic error of predicted trends rrunning far from the mean of subsequent actual temperature trend?
The fact that the actual profile of temperature trends (rather than just temperature levels) fits well the mix of trends seen in the ensemble (merely at a different date) shows that when the correct metric is used, the question of Type B error becomes less relevant.. But it is still addressed, over and over again, in the wider literature and research to seek consilience across multiple experiments.
9) Is the last decade of SST trending upward at the IPCC’s 0.2 C/decade?
Which IPCC 0.2C/decade would that be? The one come up with in a press interview by a spokesman who appears not to understand Bayes? And surely you must understand the difference between sub-decadal timescale and climate timescale.
Go ahead, explain to us your understanding of the effects of timescale in time series trendology.
