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.