Last week, Larry Kummer posted a very thoughtful article hereon WUWT:

A climate science milestone: a successful 10-year forecast!

At first glance, this did look like “a successful 10-year forecast:

The observations track closer to the model ensemble mean (P50) than most other models and the 2016 El Niño spikes at least a little bit above P50.  Noticing that this was CMIP3 model, Larry and others asked if CMIP5 (the current Climate Model Intercomparison Project) yielded the same results, to which Dr. Schmidt replied:

CMIP5 version is similar (especially after estimate of effect of misspecified forcings). http://pic.twitter.com/Q0uXGV4gHZ

— Gavin Schmidt (@ClimateOfGavin) September 20, 2017

The CMIP5 model looks a lot like the CMIP3 model… But the observations bounce between the bottom of the 95% band (P97.5) and just below P50… Then spike to P50 during the 2016 El Niño.  When asked about the “estimate of effect of misspecified forcings, Dr. Schmidt replied:

As discussed here: https://t.co/0d0mcgPq0G
(Mostly misspecification of post-2000 solar and volcanoes)

— Gavin Schmidt (@ClimateOfGavin) September 21, 2017

Basically, the model would look better if it was adjusted to match what actually happened.

The only major difference between the CMIP3 and CMIP5 model outputs was the lower boundary of the 95% band (P97.5), which lowered the mean (P50).

CMIP-5 yielded a range of 0.4° to 1.0° C in 2016, with a P50 of about 0.7° C. CMIP-3 yielded a range of 0.2° to 1.0° C in 2016, with a P50 of about 0.6° C.

They essentially went from 0.7 +/-0.3 to 0.6 +/-04.

Progress shouldn’t consist of expanding the uncertainty… unless they are admitting that the uncertainty of the models has increased.

Larry then asked Dr. Schmidt about this:

Small question: why are the 95% uncertainty ranges smaller for CMIP5 than CMIP3, by about .1 degreeC?

— Fabius Maximus (Ed.) (@FabiusMaximus01) September 22, 2017

Dr. Schmidt’s answer:

Not sure. Candidates would be: more coherent forcing across the ensemble, more realistic ENSO variability, greater # of simulations

— Gavin Schmidt (@ClimateOfGavin) September 22, 2017

“Not sure”?  That instills confidence.  He seems to be saying that the CMIP5 model (the one that failed worse than CMIP3) may have had “more coherent forcing across the ensemble, more realistic ENSO variability, greater # of simulations.”

I’m not a Twitterer, but I do have a rarely used Twitter account and I just couldn’t resist joining in on the conversation.  Within the thread, there was a discussion of Hansen et al., 1988.  And Dr. Schmidt seemed to be defending that model as being successful because the  2016 El Niño spiked the observations to “business-as-usual.”

well, you could use a little less deletion of more relevant experiments and insertion of uncertainties. https://t.co/nbAQhtjznrhttp://pic.twitter.com/gb29tm6rup

— Gavin Schmidt (@ClimateOfGavin) September 5, 2017

I asked the following question:

So… the monster El Niño of 2016, spiked from ‘CO2 stopped rising in 2000’ to “business as usual”?

— David Middleton (@dhm1353) September 25, 2017

No answer.  Dr. Schmidt is a very busy person and probably doesn’t have much time for Twitter and blogging.  So, I don’t really expect an answer.

In his post, Larry Kummer also mentioned a model by Zeke Hausfather posted on Carbon Brief…

El Niño events like 1998 and 2016 are not high probability events.  On the HadCRUT4 plot below, I have labeled several probability bands:

Standard Deviation	Probability Band	% Samples w/ Higher Values
+2σ	P02.5	2.5%
+1σ	P32	32.0%
Mean	P50	50.0%
-1σ	P68	68.0%
-2σ	P97.5	97.5%

Yes… I am assuming that HadCRTU4 is reasonably accurate and not totally a product of the Adjustocene.

I removed the linear trend, calculated a mean (P50) and two standard deviations (1σ & 2σ).  Then I added the linear trend back in to get the following:

The 1998 El Niño spiked to P02.5.  The 2016 El Niño spiked pretty close to P0.01.  A strong El Niño should spike from P50 toward P02.5.

All of the models fail in this regard.  Even the Mears-ized RSS satellite data exhibit the same relationship to the CMIP5 models as the surface data do.

–

The RSS comparison was initialized to 1979-1984.  The 1998 El Niño spiked above P02.5.  The 2016 El Niño only spiked to just above P50… Just like the Schmidt and Hausfather models.  The Schmidt model was initialized in 2000.

This flurry of claims that the models don’t “run hot” because the 2016  El Niño pushed the observations toward P50 are being driven by an inconvenient paper that was recently published in Nature Geoscience (discussed here, here and here).

Claim of a substantial gap between model projections for global temperature & observations is not true (updated with 2017 estimate): http://pic.twitter.com/YHzzXtbhs9

— Gavin Schmidt (@ClimateOfGavin) September 20, 2017

21 September 2017 0:27

Factcheck: Climate models have not ‘exaggerated’ global warming

ZEKE HAUSFATHER

A new study published in the Nature Geosciences journal this week by largely UK-based climate scientists has led to claims in the media that climate models are “wrong” and have significantly overestimated the observed warming of the planet.

Here Carbon Brief shows why such claims are a misrepresentation of the paper’s main results.

[…]

Carbon Brief

All (95%) of the models run hot, including “Gavin’s Twitter Trick”.  From Hansen et al., 1988 to CMIP5 in 2017, the 2016 El Niño spikes toward the model ensemble mean (P50)… Despite the fact that it was an extremely low probability weather event (<2.5%).  This happens irrespective of then the models are initialized.  Whether the models were initialized in 1979 or 2000, the observed temperatures all bounce from the bottom of the 95% band (P97.5) toward the ensemble mean (P50) from about 2000-2014 and then spike to P50 or slightly above during the 2016 El Niño.

By Christopher Monckton of Brenchley

When The Times, a Murdoch paper previously slavish in kow-towing to the Party Line on climate, leads with a story picked up from the more healthily skeptical Daily Mail to the effect that climate scientists have admitted “the threat of global warming is not as bad as previously thought”, one’s first instinct is to cheer.

In the climate debate, though, it pays to read the small print. Official climatology does not usually admit its many errors: instead, we are ordered to obey the “consensus”, as the Party Line is these days rebranded. On reading the headlines, I suspected at once that the true purpose of the latest admission, by Millar et al. in the current issue of Nature Geo“science”, is to minimize and thus to conceal the true magnitude of past over-predictions.

Here is how the Daily Mail reported the latest findings:

“The research by British scientists shows that, under the old projections, the world ought now to be 1.3 C° warmer than the mid-19th century average. In fact the new analysis shows it is 0.9-1.0 C° above. Michael Grubb, professor of international energy and climate change at University College London, accepted that the old projections had been wrong.”

There has been just 0.85 C° global warming since 1850, taken as the least-squares linear-regression trend on the HadCRUT4 monthly data. This not particularly thrilling rate it is equivalent to about half a degree per century. Fact-checking this part of Grubb’s statement, then, shows that his 0.9-1.0 C° observed warming since 1850 is on the high side, but not by much.

As we shall see, the Millar paper, in saying official climatology would predict only 1.3 C° global warming since 1850, has greatly understated the warming that would have been predicted. Not by coincidence, in the current issue of Nature Geovoodoo there is also a short paper by Gunnar Myhre, whose 1998 intercomparison between three climate models concluded that the CO₂ forcing had previously been overstated by 15%. Myhre’s latest paper says:

“The combined radiative forcing from all well-mixed greenhouse gases [the non-condensers, notably CO₂, methane, nitrous oxide and a sprinkling of halocarbons] was 3.1 Watts per square meter in 2015 …”, and just about all of that forcing has occurred since 1850.

To determine how much global warming official climatology would predict in response to 3.1 Watts per square meter of radiative forcing, we shall use the official “zero-dimensional model”. The equation for that model is strikingly naïve. Where w, W are pre-feedback and post-feedback global warming respectively (i.e., “reference sensitivity” and “equilibrium sensitivity”), and where f is the feedback factor,

You may well be startled – indeed, outraged – that the equation official climatology uses to tell us how much warming we’re going to get is as naïve as that. Why are we spending billions a year on IPCC if it all boils down to just that nonsensical equation? Nevertheless, I shall calibrate it to demonstrate that, naïve though it is and wrong though it is, it is indeed what climatology now uses.

If one takes official values for the inputs w, f, the equation duly spits out the official predictions of equilibrium sensitivity W. Vial et al. (2013), relied upon by IPCC (2013) for the official diagnosis of the global warming predicted by the latest generation of computer models, says that about 85% of the uncertainty in equilibrium sensitivity W arises from uncertainty in the feedback sum c, and hence in the feedback factor f, which, in the official way of doing things, is simply equal to c divided by 3.2 Kelvin per Watt per square meter.

In reality, as we shall hope to demonstrate in a learned paper before long, feedbacks have only a small influence on warming, so that the only uncertainty is in the magnitude of the forcing, but our paper proving that fact is still awaiting reviewers’ comments now three weeks overdue. For now, therefore, we shall just do things the official way, though it is egregiously at odds with mainstream science – and with experiments commissioned by us at a government laboratory, which have confirmed in every particular that we have correctly understood the mainstream science and official climatology has not.

Calibrating the official zero-dimensional-model equation proceeds thus. IPCC (2013, fig. 9.43), cites Vial et al. (2013) as having officially diagnosed the feedback sum c from simulated abrupt 4-fold increases in CO₂ concentration in 11 fifth-generation models. The 11 models’ mean value for c was 1.57 W m^–2 K^–1, implying a mid-range estimate of 0.49 for f. Vial also gave the 2 σ bounds of f as the mid-range estimate ± 40%. i.e. 0.49 ± 0.20; and the implicit CO₂ forcing, atypically including fast feedbacks, was 4.5 Watts per square meter.

The direct warming w at CO₂ doubling in Vial is thus 4.5 / 3.2 = 1.41 C°, about 20% higher than IPCC’s 1.16 C°. Using f = 0.49 and w = 1.41 C°, the zero-dimensional model equation yields an interval of equilibrium sensitivities W of 2.0-4.5 C° in response to doubled CO₂, as shown in bold type in the table. Since the values the equation determines from official inputs are near-perfectly coextensive with many published official intervals, the equation is duly calibrated. Like it or not (and you shouldn’t), it is what the Forces of Darkness use.

The only discrepancy is in the central estimate of post-feedback global warming, where the zero-dimensional model predicts 2.8 K and the published official estimates predict 3.3 K.

This discrepancy arises because official climatology occasionally forgets that the curve of the zero-dimensional-model equation is not a straight line but a rectangular hyperbola (see above). Using IPCC’s 3.0 [1.5, 4.5] C° official range of predicted equilibrium sensitivities to doubled CO₂, a mid-range estimate f = 0.49 for the feedback factor visibly implies a mid-range estimate of 2.25 C° for post-feedback global warming, not the 3 C° imagined by IPCC, and still less the 3.3 C° that is the CMIP5 models’ mid-range projection.

One can, therefore, determine the implicit mid-range estimate of post-feedback warming in the fifth-generation models by using the zero-dimensional-model equation. Where the direct or pre-feedback warming w in response to doubled CO₂ concentration is 1.16 K, and where the post-feedback warming W is predicted to be 3.3 K, as the CMIP5 models predict, the feedback factor implicit in that prediction is 1 – (1.16 / 3.3) = 0.65.

Now we have enough information to determine the global warming that the CMIP5 models would predict in response to the 3.1 Watts per square meter of radiative forcing, from all anthropogenic sources, that Myhre (2017) says has occurred since about 1850. The direct or pre-feedback warming is simply 3.1 / 3.2, or about 1 C°. Using the now-calibrated but dumb official zero-dimensional-model equation from above, the post-feedback warming that he CMIP5 models would have predicted since 1850 is 1 / (1 – 0.65), or 2.75 C°, more than twice the 1.3 C° mentioned in the Millar paper and more than three times the 0.85 C° of global warming that has actually occurred.

For comparison, our corrected version of the zero-dimensional-model equation would have predicted 1.2 C° warming in response to 3.1 Watts per square meter of anthropogenic forcing since 1850, far closer to the 0.85 C° that was observed than official climatology’s 2.75 K.

One could do a similar analysis based on the statement in IPCC (2013) that there had been 2.3 Watts per square meter of anthropogenic radiative forcing since pre-industrial times, implying 2.05 C° global warming to date, or almost thrice the 0.75 C° observed from 1850-2011 according to the HadCRUT4 dataset. Our equation would have predicted 1.0 C°, again far closer to observed reality than the 2.05 C° that the official equation would predict.

Or one could compare IPCC’s central prediction in 1990 that in the 36 years 1990-2025 there would be 1 C° global warming (equivalent to 0.75 C° in the 27 years 1990-2016) with the actual warming of 0.45 C° over the period, taken as the mean of two terrestrial and two satellite datasets. Again, the unsoundly-based official prediction is a substantial exaggeration compared with the observed outturn, but our corrected model comes much closer to the truth, suggesting 0.37 C° warming, far closer to the 0.45 C° that actually occurred than the 0.75 C° that IPCC had predicted.

Professor Myles Allen of Oxford University is cited by the Daily Mail as having said that if the world followed “ambitious” reductions in CO₂ emissions there would be even odds of meeting the unscientific Paris aspiration of a Canute-like restriction of global temperature to 1.5 C° above the pre-industrial value, equivalent to 0.65 C° above today’s global mean surface temperature. However, on present trends CO₂ concentration will rise from 400 to 650 ppmv by 2100, causing a direct warming of 0.8 C°, with a further 0.2 C° contributed by temperature feedbacks. The 1.5 C° aspiration, therefore, will not be met even using our mainstream equation rather than official climatology’s defective equation.

Unless, that is, Professors Harde and Happer are right that the CO₂ forcing, as well as the feedbacks on which our paper concentrates, has been exaggerated. Professor Harde has estimated that it is overstated by 30%; Professor Happer, for a different reason that does not overlap with Professor Harde’s conclusion, says the CO₂ forcing has been overestimated by 40%. If both Professors are right, the CO₂ forcing has been over-predicted by 82%. If we are also right, then the direct warming this century will be 0.45 C°, with another 0.1 C° from feedbacks. Though there are other greenhouse gases, these are more or less exactly offset by negative anthropogenic forcings, so that, even without any mitigation efforts in this century, the Paris ambition will in reality be met by 2100. And, if the world warms by more than 0.65 C° compared to today, but does not do so till after 2100, the rate of warming will be too slow to be dangerous,. There is now no need for the UNFCCC or for the IPCC. Abolish both.

Official climatology has vastly exaggerated its predictions. Its disfiguring attempts to conceal the true extent of the discrepancy between exaggerated prediction and unexciting observation will fail. That discrepancy is attributable to errors chiefly in the representation of feedbacks in the zero-dimensional and, inferentially, in the three-dimensional models whose outputs the simple equation faithfully reproduces, indicating its efficacy as a black-box diagnostic. Correction of the errors in the official equation generates predictions far less extreme and far closer to real-world observation than the wild exaggerations on the basis of which governmental and intergovernmental entities have hitherto profitably panicked.

Though the Millar paper serves to conceal the true extent of the official exaggerations on which demands for “climate action” have been unwisely based, it is at another level an early crack in the dam that indicates that the entire edifice of nonsense is about to fail. Have courage! The truth that global warming will be small, harmless and net-beneficial will soon prevail over the screeching extremists. The Millar paper is not the beginning of the end, but it is at least the end of the beginning.