The Abject Failure of Official Global-Warming Predictions

By Monckton of Brenchley – Re-Blogged From http://www.WattsUpWithThat.com

The IPCC published its First Assessment Report a quarter of a century ago, in 1990. The Second Assessment Report came out 20 years ago, the Third 15 years ago. Even 15 years is enough to test whether the models’ predictions have proven prophetic. In 2008, NOAA’s report on the State of the Global Climate, published as a supplement to the Bulletin of the American Meteorological Society, said: “The simulations rule out (at the 95% level) zero trends for intervals of 15 yr or more, suggesting that an observed absence of warming of this duration is needed to create a discrepancy with the expected present-day warming rate.”

To the continuing embarrassment of the profiteers of doom, the least-squares linear-regression trends on Dr Roy Spencer’s UAH satellite dataset shows no global warming at all for 18 years 6 months, despite a continuing (and gently accelerating) increase in atmospheric CO2 concentration, shown on the graph as a gray trace:

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Dr Carl Mears’ RSS dataset shows no global warming for 18 years 8 months:

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By contrast, the mean of the three much-altered terrestrial tamperature datasets since May 1997 shows a warming equivalent to a not very exciting 1.1 C°/century:

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It is now time to display the graph that will bring the global warming scare to an end (or, at least, in a rational scientific debate it would raise serious questions):

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The zones colored orange and red, bounded by the two red needles, are, respectively, the low-end and high-end medium-term predictions made by the IPCC in 1990 that global temperature would rise by 1.0 [0.7, 1.5] Cº in the 36 years to 2025, equivalent to 2.78 [1.94, 4.17] Cº/century (page xxiv). The boundary between the two zones is the IPCC’s then best prediction: warming equivalent to about 2.8 C°/century by now.

The green region shows the range of measured global temperatures over the quarter-century since 1990. GISS, as usual following the alterations that were made to all three terrestrial datasets in the two years preceding the Paris climate conference, gives the highest value, at 1.71 C°/century equivalent. The UAH and RSS datasets are at the lower bound of observation, at 1.00 and 1.11 C°/century respectively.

Two remarkable facts stand out. First, the entire interval of observational measurements is below the IPCC’s least estimate in 1990, individual measurements falling between one-half and one-third of the IPCC’s then central estimate.

Secondly, the interval between the UAH and GISS measurements is very large – 0.71 C°/century equivalent. The GISS warming rate is higher by 71% than the UAH warming rate – and these are measured rates. But the central IPCC predicted rate is not far short of thrice the UAH measured rate, and the highest predicted rate is more than four times the UAH measured rate.

The absolute minimum uncertainty in the observational global-temperature measurements is thus 0.71 C°/century, the difference between the UAH and GISS measured warming rates. Strictly speaking, therefore, it is not possible to be sure that any global warming has occurred unless the warming rate is at least 0.71 C° century. On the mean of the RSS and UAH datasets, the farthest one can go back in the data and yet obtain a rate less than 0.71 C° is August 1993.

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In short, the Pause may in reality be as long as 22 years 5 months – and the more the unduly politicized keepers of the terrestrial records tamper with them with the effect of boosting the rate of warming above the true rate the more they widen the observational uncertainty and hence increase the possible length of the Pause.

In 1995 the IPCC offered a prediction of the warming rates to be expected in response to various rates of increase in CO2 concentration:

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The actual increase in CO2 concentration in the two decades since 1995 has been 0.5% per year. So there should have been 0.36 C° global warming since then, equivalent to 1.8o C°/century, as shown by the single red needle above.

Once again the graph comparing observation with prediction displays some remarkable features. First, the IPCC’s 1995 prediction of the warming rate to the present on the basis of what has turned out to be the actual change in CO2 concentration over the period since 1995 was below the entire interval of predictions of the warming rate in its 1990 report.

Secondly, all five of the principal global-temperature datasets show warming rates below even the IPCC’s new and very much lower predicted warming rate.

Thirdly, the spread of temperature measurements is wide: 0.38 C°/century equivalent for UAH, up to 1.51 C°/century equivalent for GISS, a staggeringly wide interval of 1.17 C°/century. The GISS warming rate over the past two decades is four times the UAH warming rate.

Fourthly, the measured warming rate has declined compared with that measured since 1990, even though CO2 concentration has continued to increase.

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So to the 2001 Third Assessment Report. Here, the IPCC, at page 8 of the Summary for Policymakers, says: “For the periods 1990-2025 and 1990to 2050, the projected increses are 0.4-1.1 C° and 0.8-2.6 C° respectively.” The centennial-equivalent upper and lower bounds are shown by the two red needles in the graph above.

Once again, there are some remarkable revelations in this graph.

First, both the upper and lower bounds of the interval of predicted medium-term warming, here indicated by the two red needles, have been greatly reduced compared with their values in 1990. The upper bound is now down from 4.17 to just 3.06 C°/century equivalent.

Secondly, the spread between the least and greatest measured warming rates remains wide: from –0.11 C°/century equivalent on the RSS dataset to +1.4 C°/century equivalent on the NCEI dataset, an interval of 1.51 C°/century equivalent. Here, as with the 1990 and 1995 graphs, the two satellite datasets are at the lower bound and the terrestrial datasets at or close to the upper bound.

Which datasets are more likely to be correct, the terrestrial or the satellite datasets?

The answer, based on the first-class research conducted by Anthony Watts and his colleagues in a poster presentation for the Fall 2015 meeting of the American Geophysical Union, is that the satellite datasets are closer to the truth than the terrestrial datasets, though even the satellite datasets may be suffering from urban heat-island contamination to some degree, so that even they may be overstating the true rate of global warming. The following graph shows the position:

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NOAA’s much-altered dataset (J. Karl, prop., say no more) appears to have overstated the true warming rate by some 60%. Watts et al. determined the true warming rate over the continental United States by a sensible and straightforward method: they adopted as normative a standard for the ideal siting and maintenance of temperature monitoring stations that had been independently drawn up and peer reviewed, and then they applied that standard to all the stations in the contiguous United States, excluding all stations that did not comply with the standard. The result, in blue, is that from 1979-2008 the true rate of warming over the continental U.S. was not the 3.2 C°/century equivalent found by NOAA, nor even the 2.3 C°/century equivalent found by UAH, which keeps a separate record for the 48 states of the contiguous U.S., but just 2.0 C°/century equivalent.

On this evidence, the satellites are far closer to the mark than the terrestrial datasets.

Thirdly, the measured rate of warming has again fallen, directly in opposition to the continuing (and gently accelerating) increase in atmospheric CO2 concentration and in anthropogenic forcings generally.

This inexorably widening divergence between prediction and reality is a real and unexplained challenge to the modelers and their over-excited, over-egged predictions. The warming rate should be increasing in response not only to past forcings but also to the growth in current anthropogenic forcings. Yet it has been declining since the mid-1980s, as the following interesting graph shows:

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At no point has the rate of global warming reached the lower bound of the interval of global warming rates predicted by the IPCC in 1990:

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Displaying the three prediction-vs.-reality graphs side by side shows just how badly off beam have been the official predictions on the basis of which governments continue to squander trillions.

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The graphs show between them a failure of prediction that is nothing less than abject. The discrepancies between prediction and observation are far too great, and far too persistent, and far too contrary to the official notion of high climate sensitivity, to be explained away.

The West is purposelessly destroying its industries, its workers’ jobs, its prosperity, its countryside, and above all its scientific credibility, by continuing to allow an unholy mesalliance of politicians, profiteers, academics, environmental extremists, journalists and hard-left activists to proclaim, in defiance of the data now plainly shown for all to see for the first time, that the real rate of global warming is “worse than we thought”. It isn’t.

CONTINUE READING –>

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