The ever irascible Paul Williams is at it again, threatening to do a Michael Mann number on a journalist who critically reported on his research purporting to demonstrate a strong link between climate change and increased clear air turbulence (CAT):
He makes several claims in a long thread to back up his claim that he has been defamed by the author of the article. In particular:
As Roger Pielke Jr. rightly pointed out in response to Williams, the author did not claim that Williams’ 2022 paper had been retracted; she only said that the central claim of the paper had been retracted - by Williams himself. This is what Rupa Subramanya actually wrote:
But how solid is his link between clear air turbulence and climate change? Earlier this year, Williams co-authored a letter to the Quarterly Journal of the Royal Meteorological Society, which walked back the findings of his 2022 paper. If we include new data, the letter explained, the increase in wind speeds above the North Atlantic ceases to be “statistically significant.”
As is often the case—whether the subject of a study is vaccines or mental illness—the retraction received far less attention from the press than the original claim.
She is obviously using the word ‘retraction’ in the wider sense here, not implying that the paper itself was retracted. Williams only screenshots the second paragraph to give the impression that she did claim that his paper was retracted. This is dishonest and devious and he should apologise. Or maybe Ms Subramanya should sue Williams for defamation?
Next, Williams huffs and puffs about Subramanya’s claim that a proposed increase in jet stream wind speed forms the basis of the claim that CAT has increased due to climate change. This is a bit more subtle and Williams is partly justified in criticising the author, but not wholly justified as it turns out.
Her ‘basic scientific error’ was the claim that turbulence is caused by jet stream wind speed and that it is the sole basis for arguing that CAT will get worse. It’s a bit more complicated than that. As Williams correctly states, the direct cause of CAT is wind shear (vertical wind shear to be more precise). He then goes on to make the claim that wind shear has ‘clearly increased’:
That paper was published in 2019. But in 2022, Williams was again emphasising an increase in the basic jet stream wind speed alone, which, with the additional couple of years data to date has now tuned out to be “statistically insignificant” and hence Williams has ‘retracted’ the 2022 claim, as pointed out by Subramanya. Hence he’s now refocusing on the claim that ‘wind shear’ has increased and castigating Subramanya for even suggesting that jet stream wind speed is a determining factor in creating increased turbulence. We can get an idea of the evolution of Williams’ thinking on this whole issue from 2017 onwards, which suggests that he is not being totally intellectually honest. Because in 2017, Williams authored a study which says:
In the field of aviation turbulence, observational studies generally support the hypothesis that clear-air turbulence is generated by the breaking of unstable Kelvin–Helmholtz waves in highly sheared regions of the atmosphere (Endlich, 1964; Atlas et al., 1970; Watkins and Browning, 1973). This hypothesis concurs with evidence that the jet stream contains about three times more clear-air turbulence than the rest of the atmosphere (Reiter, 1963, Section 9.2). The hypothesis also concurs with evidence that eastbound transatlantic flights, being closer to the strong tailwinds in the core of the jet stream, encounter more clear-air turbulence than westbound transatlantic flights (Kim et al., 2016).
https://link.springer.com/article/10.1007/s00376-017-6268-2
It seems that all this stuff isn’t even ‘settled science’, but it’s clear from what Williams said above in 2017 that jet stream wind speeds are very important in determining the wind shear and hence the degree of turbulence.
Then in 2019, when there was no multidecadal signal of increasing jet stream wind speed, Williams pivoted to focusing on wind shear:
Earth’s equator-to-pole temperature gradient drives westerly mid-latitude jet streams through thermal wind balance. In the upper atmosphere, anthropogenic climate change is strengthening this meridional temperature gradient by cooling the polar lower stratosphere and warming the tropical upper troposphere, acting to strengthen the upper-level jet stream. In contrast, in the lower atmosphere, Arctic amplification of global warming is weakening the meridional temperature gradient, acting to weaken the upper-level jet stream. Therefore, trends in the speed of the upper-level jet stream represent a closely balanced tug-of-war between two competing effects at different altitudes. It is possible to isolate one of the competing effects by analysing the vertical shear—the change in wind speed with height—instead of the wind speed, but this approach has not previously been taken. Here we show that, although the zonal wind speed in the North Atlantic polar jet stream at 250 hectopascals has not changed since the start of the observational satellite era in 1979, the vertical shear has increased by 15 per cent (with a range of 11–17 per cent) according to three different reanalysis datasets. We further show that this trend is attributable to the thermal wind response to the enhanced upper-level meridional temperature gradient. Our results indicate that climate change may be having a larger impact on the North Atlantic jet stream than previously thought. The increased vertical shear is consistent with the intensification of shear-driven clear-air turbulence expected from climate change, which will affect aviation in the busy transatlantic flight corridor by creating a more turbulent flying environment for aircraft. We conclude that the effects of climate change and variability on the upper-level jet stream are being partly obscured by the traditional focus on wind speed rather than wind shear.
Three years later, Williams had apparently detected a significant trend in jet stream wind speed (not since 1979, but from 2002-2020):
Multiple studies have considered whether increased anthropogenic CO2 will affect the wind speeds and turbulence associated with the winter North Atlantic polar-front jet stream in the upper atmosphere.
. . . . . . for the last roughly 20 years (2002–2020) both the ERA5 reanalysis (2.5% per year) and the GADS archive (1.2% to 1.4% per year) show a statistically significant rise in the wind speed in the North Atlantic jet streak exit region.
https://rmets.onlinelibrary.wiley.com/doi/10.1002/qj.4342
Then in 2024:
The result is that the primary conclusion of Tenenbaum et al. (2022), that the wind speeds near the North Atlantic winter jet stream exit region increased by 2.5% per year, changes to 1.4% per year. But more crucially, it is no longer statistically significant.
https://rmets.onlinelibrary.wiley.com/doi/full/10.1002/qj.4676
Subramanya pointed this out in her article and Williams is not happy, because he’s spent years trying to prove his theory that the jet stream is being seriously affected by man-made climate change and that severe turbulence is increasing as a result. Too bad. You can’t play fast and loose with the facts. Data is data and if it doesn’t fit your theory, or hypothesis, then your theory must remain on the drawing board and just because one aircraft has encountered very severe clear air turbulence, with one man unfortunately dying as a result, this does not mean that your pet theory is suddenly ‘fact’. And it doesn’t mean that you can go round threatening to sue people for pointing out the facts, even if they don’t do it precisely enough for your satisfaction.
Well done for following this chicanery, so we don't have to.
He comes across as a sensitive little, pearl clutching, crybaby.
How dare anyone point out his mistakes, thus causing him " a great deal of distress".
Parthetic little man.