The need to exercise caution

It seems nowadays that there is barely a day goes by without somewhere in the world there being a report of record wildfires, heatwaves, floods or storms. The dire warnings of a distant, apocalyptic future are still as shrill as ever but now they are abundantly illustrated by reference to everything bad that the weather is throwing at us here and now. Each such report has a dual purpose, to emphasise the calamity befallen and to remind everyone that experts say climate change is destined to increase both frequency and severity. Furthermore, there will always be someone on hand to vouch for the disaster having been on a scale never seen before. It’s a winning narrative that is providing the motivation for everything net zero.

The favoured cliché used in such reports is that of the wake-up call. Unsurprisingly, therefore, subtlety has not been the objective, any more than it is for my alarm clock. No sooner has the reader stopped reeling from the distressing detail, he or she is then authoritatively warned that they could be next – and there’s even worse in store for their children. At first blush, there seems no avoiding the obvious conclusions. You can’t sleep through it because it is designed not to be slept through.

This design feature can be traced back to the point where the IPCC made it clear in their Fifth Assessment Report (AR5) that an increased emphasis on extreme weather events is to form a central strategy in encouraging society to buy into the net zero project. Such a shift would inevitably result in a queue of experts rationalising the new order by saying things are worse than they thought, i.e. things are happening a lot quicker than the science had suggested. Despite all of the confident predictions, it turns out they had all got it wrong, but in a good way if you are one of those calling for a climate change emergency to be declared.

Most climate change sceptics accept that the climate is changing and there is an anthropogenic component, but their continued opposition to current net zero plans has to be thoroughly discredited. With the new focus upon extreme weather events, climate change appeared to have become starkly evidence-based and complaints about an over-reliance on models wasn’t going to cut it anymore. Even so, in order to achieve this, the IPCC had to put it’s thumb on the scales. For that reason, caution should be exercised whenever evaluating a news report that covers an extreme weather event.

The Kentucky Floods

I’d like to illustrate the exploitative nature of extreme weather event reporting by reference to the recent Kentucky floods. I will be looking at a particular BBC report and, as always, context will be the all-important consideration. With the floods taken out of their correct context, the IPCC’s thumbprint can be discerned in the reporting.

Looking at the BBC report, it is evident that all the necessary components are there. Firstly, there is an emphasis on the scale and full horror of the event:

“President Joe Biden has declared the floods ‘a major disaster’ and ordered federal aid to help local rescuers. Among the dead are at least six children, including a one-year-old.”

Immediately followed by an authoritative link to climate change:

“Scientists say climate change is triggering more extreme weather events like the Kentucky flooding.”

Then there is the testimony that the event is unprecedented:

Appalachia has had flash floods before, but not on this scale, [Kentucky Governor] Mr Beshear said. ‘Folks who deal with this for a living, who have been doing it for 20 years, have never seen water this high,’ he said.”

More distressing details are added before the report widens its scope:

“Kentucky, like other parts of the world, has seen the impact of more frequent extreme weather events.”

We are then provided with another authoritative claim that this is something new:

“The state has seen more inches of rain outside the historical average in the last 10 years, according to date [sic] from the National Oceanic and Atmospheric Administration. Bill Haneberg, a climate expert and the state’s geologist, said this rainfall event is ‘extraordinary’ for Kentucky.”

The only thing missing this time around is the confession that scientists had got it wrong by thinking this sort of thing wouldn’t be happening just yet. On the contrary, in this version of the narrative it was all foreseen:

 “He added that the increases in the amount of rainfall over the years are consistent with what experts have predicted for the region – that Kentucky’s climate would become hotter and wetter due to climate change.”

Finally, there is the gratuitous mentioning of another extreme weather bête noire:

“The historic flooding comes as the state recovers from the deadliest tornadoes in its history, which killed more than 70 in December 2021.”

It is all very alarming. But now let’s add a little bit of context.

A sober reappraisal

Firstly, I need to say that no one could accuse Biden of exaggerating the scale of the disaster or just how terrible it was. It was indeed catastrophic. However, I am prepared to be cynical enough to suggest that the sheer scale of the disaster is the feature that singles it out for the full climate change treatment. Only the avoidance of catastrophic events could possibly justify the pain to be experienced trying to achieve net zero, and justification is what this is all about. The Kentucky floods meet the first important criterion – they were horrendous. It is that fact that gives the juxtaposition of the opening two quotes its potency. The only weakness is the lack of a categorical connection, as it could only be ‘events like the Kentucky flooding’.

However, the weak connection is not something the BBC report is prepared to dwell upon. The important point to take home, apparently, is that this was an unprecedented flood. Except it wasn’t – and far from it. It’s all very well for ‘Folks who deal with this for a living, who have been doing it for 20 years’  to be sharing their experience but a proper perspective requires a much longer timescale. And if one looks far back enough, one fact becomes abundantly clear: Kentucky is notorious for its abundant precipitation and for suffering severe flash flooding. To quote the National Weather Service:

“Floods have been ravaging settlers in the Ohio and Tennessee valleys since they arrived.”

This was not an unprecedented flood but it was the worst since 1937. However, the important point is whether precipitation and flash flooding has gradually worsened since 1937, in the way Kentucky’s state geologist says had been predicted. This is the key connection that could justify linking the disaster to climate change. Unfortunately, this is where things become particularly problematic for the climate change narrative.

The awkward fact is that the state of Kentucky has not actually experienced any net warming since 1937 (a fate shared with the rest of south eastern USA). Whilst there has been some warming over recent years this has only compensated for a prolonged period of cooling, such that temperatures are now only just exceeding their 1930s levels. According to the NOAA:

“Temperatures in Kentucky have risen by 0.6°F, less than half of the warming for the contiguous United States, since the beginning of the 20th century, but the warmest consecutive 5-year interval was 2016–2020. Very warm temperatures occurred during the 1930s, followed by a substantial cooling of about 2°F in the 1960s. Since then, temperatures have risen about 3°F and have exceeded the highs of the 1930s. The hottest year on record was 1921, but two recent years, 2012 and 1998, rank second and third, respectively. Because of the cooling in the mid-20th century, the southeastern United States is one of the few regions globally that has experienced little to no overall warming since 1900.”

And when one focusses in on the numbers of extremely hot days, the picture remains broadly the same, as illustrated below:

Similarly with precipitation levels. Kentucky’s geography has always rendered it vulnerable to high precipitation, and the recent 10 year period of above average levels should be taken in its proper context, in as much as it follows on from a long and relatively stable period that was defying the predicted rises. The reality is that the rainfall event was anything but ‘extraordinary’ and current annual rainfall is not appreciably higher than the past. This can be seen by examining the full NOAA dataset from which the BBC report chose to cherry-pick. There is a very recent upward trend but not one that jumps out of the page:

The bottom line is that context is always important and never more so than for the recent Kentucky floods. The BBC report was written to alarm, and in that respect it succeeds admirably; a lot of people would have been woken up by it. However, a more sober and accurate reporting would have read as follows:

“Once again the long-suffering state of Kentucky has been struck down by yet another bout of prolonged and heavy rain resulting in flash flooding for which the state is notorious. If anything, climate change may have made the floods a little more severe than normal, though making such a connection would be problematic given that Kentucky and neighbouring states haven’t actually experienced any warming when viewed over the relevant timescales.”

Still want to spend those trillions on net zero?

29 Comments

  1. Yet again, where are the BBC’s climate disinformation specialists when you need them? They certainly never bother fact-checking the garbage coming out of the BBC.

    Liked by 1 person

  2. It is only natural for the State Governor to blame climate change. The alternative explanation is that there were local failings which were within his power to avert. If I was a local I would be outraged: not by the world’s reluctance to give up oil etc, but by the inability to prevent deaths from flooding in a modern, wealthy country. There seems to be a State Climatologist and a State Geologist and presumably a State Percussionist and a State Proctologist – so also one assumes there is a State Meteorologist, whose timely forecast should have been used by local government officials to go door-to-door and ensure that no-one in the extreme risk zone had not been evacuated.

    Liked by 1 person

  3. Mark, Jit,

    To be fair, the BBC and the Kentucky Governor are just quoting what scientists are prepared to say to the camera. Whether or not such statements fairly reflect the trends in climate over the last century is debatable. For example, here’s another graph that I might have added to the article. Once again, it demonstrates that the trend for increased extreme precipitation events is not particularly strong and that words such as ‘unprecedented’ should be used more cautiously:

    Like

  4. That said, if Ed Hawkins got hold of the data I’m sure he would be able to conjour up something that reveals the true horror.

    Liked by 1 person

  5. “Unprecedented” now seems to mean something that some people haven’t seen in the last 20 years.

    Liked by 1 person

  6. Well, today, on the Commonwealth Games Web page, there is another lunatic article about how “climate change” will affect sport (and therefore the Games) in the future highlighted by a load od excrement about recent “extreme” weather events – I really despair of what rubbish the BEEB will produce in the future!!!

    Like

  7. I’ve been thinking a bit more as to why I challenged the claim that the recent flooding was ‘extraordinary’. After all, it was a once in a hundred years flood, and if that doesn’t count as being extraordinary, then what does?

    After giving it some thought, I have come to the following conclusion: The reason why it is not extraordinary is because it is a once in a hundred years flood that happened about 85 years after the last one, and there is nothing extraordinary about that. The attribution experts draw their causation conclusions by running the models with and without the anthropogenic component to see how the probabilities change. In this case, the models are not a good basis for such a calculation because they predicted much more warming than has actually occurred in Kentucky (contrary to what the state geologist claims). This rain event was within expectations if one looks at the historical records (particularly if one takes into account what the NOAA refers to as the ‘high variability’ of such events in Kentucky). However, if one looks at the models one would have to say it was somewhat late in occurring and not as severe as predicted.

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  8. John, the issue is that you have made a sober appraisal of the Kentucky floods, putting them in their historical context and applying logic to the situation. I wouldn’t apply for a job at the Guardian or the BBC just now; I don’t think you have the right qualifications. 🙂

    Liked by 3 people

  9. Meanwhile, is this a sober appraisal?

    “US extreme weather ‘reminder of intensifying impacts of climate change’ – White House”

    https://www.theguardian.com/us-news/live/2022/aug/08/biden-visits-kentucky-floods-senate-passes-739bn-healthcare-climate-bill-us-politics-latest-updates

    “On Joe Biden’s visit to flood-ravaged eastern Kentucky today he is not just viewing the effects through the lens of a disaster needing federal assistance but also through the lens of the climate crisis that is making events like this more intense, more common and more deadly, in America and around the world.

    White House press secretary Karine Jean-Pierre addressed the issue in her media briefing aboard Air Force One en route to Lexington with the US president and first lady Jill Biden a little earlier.

    “The floods in Kentucky and extreme weather all around the country are yet another reminder of the intensifying and accelerating impacts of climate change and the urgent need to invest in making our communities more resilient to it,” she said….”.

    Liked by 2 people

  10. John – a bit O/T but you mention models in above comment.

    i’ve noticed the BBC weather presenters (maybe other channels) saying something like “our models predict a bit rain in the west”
    this “our models” statement seems a recent thing.to me.
    when the BeeB moved to MeteoGroup I thought we might get less alarmism in forecasts, alas no.

    WIKI – partial quote –
    On 6 February 2018 BBC Weather changed supplier from the government Met Office to MeteoGroup, after being required to put its weather services out to tender.[13] Some have claimed there has been a reduction in accuracy of BBC forecasts as a result.

    Like

  11. “South Korea flood: record rain kills at least 7 in Seoul with more falls expected
    Seven people remain missing amid fears of further damage with torrential rain forecast in some parts of the country on Wednesday”

    https://www.theguardian.com/world/2022/aug/09/south-korea-flood-2022-weather-record-rain-seoul

    Not a sober headline, tragic though the story is. In what sense is it “record rain” when, according to the Guardian itself, in the article written under the headline:

    “Rainfall of more than 100mm an hour was recorded in Seoul, surrounding areas of Gyeonggi province and the port city of Incheon on Monday night, according to the Yonhap news agency. Per-hour precipitation in the Dongjak district surpassed 141.5mm at one point, the heaviest hourly downpour in Seoul for 80 years.”

    So it hasn’t broken an 80-year old (or longer?) record. At least the BBC manages a more sober (and accurate) appraisal in its headline:

    “Seoul floods: At least eight dead amid heaviest rain in decades”

    https://www.bbc.co.uk/news/world-asia-62462275

    “Some areas received the highest rate of rainfall in 80 years, Korea’s meteorological agency said.”

    The BBC managed to avoid talking about climate change, but the Guardian just couldn’t help itself:

    “South Korea is no stranger to heavy rainfall in the summer, but a meteorological administration official said the climate emergency had caused a sharp increase in precipitation and frequent torrential rains.

    “This phenomenon is occurring more often due to climate change, which has resulted in a prolonged summer,” the official said on condition of anonymity.”

    It’s a pretty pass when the only person they can find prepared to make the link for them is someone who insists on anonymity.

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  12. Mark,

    For those such as the White House press secretary maybe a little arithmetic may help. A 1-in-100 years flood is defined as one in which there is a 1% chance of it happening in any given year. So to calculate the chances of escaping one for n years after an occurrence you have to raise 0.99 to the power n. If n=85 the answer is very close to 0.5. That is to say there is a fifty-fifty chance that the Kentucky flood would happen anyway even without warming. Since there has been no such warming in Kentucky over the relevant period, I’d say the flood was on schedule and to be expected. If these people want to use such extremes to make their case then they need to look elsewhere. But that would be to miss a glorious opportunity. By design or through folly, such events have the power to persuade.

    If they were to focus instead on less extreme events they might be able to discern a suggestive trend, albeit only over recent years. But that is not the name of the game. It wouldn’t be enough to release the billions and to have the Democrats weeping with joy.

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  13. Dfhunter,

    I too have noticed that weather presenters are mentioning their models more often. The recent record-breaking heatwave, for example, was presaged by the weather presenter saying that the record for the highest temperature in their predictive models had been broken. Although they conceded the probabilities involved were very low it was still as if it had some physical significance.

    As for the accuracy of BBC weather forecasts, I have never found them to be particularly so for where I live.

    Like

  14. John (yesterday):

    I’ve been thinking a bit more as to why I challenged the claim that the recent flooding was ‘extraordinary’. After all, it was a once in a hundred years flood, and if that doesn’t count as being extraordinary, then what does?

    After giving it some thought, I have come to the following conclusion: The reason why it is not extraordinary is because it is a once in a hundred years flood that happened about 85 years after the last one, and there is nothing extraordinary about that.

    Totally with you so far.

    The attribution experts draw their causation conclusions by running the models with and without the anthropogenic component to see how the probabilities change. In this case, the models are not a good basis for such a calculation because they predicted much more warming than has actually occurred in Kentucky (contrary to what the state geologist claims).

    Oh dear, oh dear, oh dear.

    Very good point (earlier) that Kentucky hasn’t had any net warming since 1937. And this shows that the models are lousy at local forecasting, which they are known to be all over the shop, where shop = globe.

    But this method that the ‘attribution experts’ use is baloney. This “we ran it with this much man-made greenhouse gas emissions” vs “we ran it with less man-made greenhouse gas emissions” and “we actually proved something”. No you didn’t. Take it from me. Or, rather better, take it from von Neumann and Fermi and Dyson:

    Prof. Dyson learned about the pitfalls of modelling early in his career, in 1953, and from good authority: physicist Enrico Fermi, who had built the first nuclear reactor in 1942. The young Prof. Dyson and his team of graduate students and post-docs had proudly developed what seemed like a remarkably reliable model of subatomic behaviour that corresponded with Fermi’s actual measurements. To Prof. Dyson’s dismay, Fermi quickly dismissed his model. “In desperation, I asked Fermi whether he was not impressed by the agreement between our calculated numbers and his measured numbers. He replied, ‘How many arbitrary parameters did you use for your calculations?’ I thought for a moment about our cut-off procedures and said, ‘Four.’ He said, ‘I remember my friend Johnny von Neumann [the co-creator of game theory] used to say, with four parameters I can fit an elephant, and with five I can make him wiggle his trunk.’ With that, the conversation was over.” Prof. Dyson soon abandoned this line of inquiry. Only years later, after Fermi’s death, did new developments in science confirm that the impressive agreement between Prof. Dyson’s model and Fermi’s measurements was bogus, and that Prof. Dyson and his students had been spared years of grief by Fermi’s wise dismissal of his speculative model. Although it seemed elegant, it was no foundation upon which to base sound science.

    — Larry Solomon in April 2007
    (once at http://www.nationalpost.com/news/story.html?id=985641c9-8594-43c2-802d-947d65555e8e now another victim of bit rot)

    These ‘climate models’ have tons of ‘arbitrary parameters’. They are proving nothing of the sort. Where ‘the sort’ is anything of significance at all.

    Early in the 2000s I first came across this kind of argument as I looked for the ‘real science’ behind climate alarm. I thought there must be some, trusting fellow that I was. This is what it came down to, this kind of game played with highly complex models, showing that climate sensitivity (ECS) was high and thus … (also unexplained) … calamity for humanity. And I thought at once: “You mean they’ve got *nothing*?” I was astounded.

    We’re back to The Hunting of the Snark: “What I tell you three times is true.” Sorry, no, it was wrong then and it’s wrong now.

    Like

  15. When it comes to scientism it’s always worth remembering William Briggs’ admonition:

    Repeat after me: all models only say what they are told to say.

    Like

  16. It seemed strange to me that Kentucky hasn’t warmed much if at all over a time period when much of the rest of the USA has apparently warmed.

    Its population is only around 4.5 million, and its biggest city is Louisville, whose extended metropolitan area has a population of perhaps 1.4 million. That is, in the scheme of things, a fairly small city, certainly compared to many around the world and elsewhere in the US.

    And so I wonder if Kentucky’s lack of warming is due to a lack of much of an urban heat island effect. If so, does it mean that much of the warming elsewhere isn’t real, but instead is a function of UHI?

    Like

  17. Richard,

    I don’t think we have any fundamental difference of opinion here. I think there are two issues to consider. Firstly, is exploring counterfactuals in models a valid means of discerning causality, and to that question I give a resounding yes. Secondly, there is the question of whether the answers are particularly useful when that technique is used on these particular models, and the answer to that question is very much still open. I don’t think I can do any better than repeat what I said on this subject in my ‘Brief Primer on Causation’:

    A Brief Primer on Causation

    “With a SCM [Structural Causal Model], one can model the counterfactual simply by altering the values associated with a causal agent to see what the impact is. This is precisely what happens when climate models are re-run with anthropogenic emissions removed, in order to see how a prediction or retrodiction changes. The difference is interpreted causally, and there is nothing wrong with that. However, there are two important details regarding the modelling of the counterfactual that need to be mentioned here.”

    In describing the first important detail, I go on to say:

    “The problem with such attribution studies is that they are premised upon models that are notoriously compromised in their role as material witness. If one turns a blind eye to their structural uncertainties one can confidently draw causal inferences by playing the counterfactual game. But is it wise to turn a blind eye to structural uncertainty in a structural causal model? If one is going to evaluate as one would in a legal case, then one must forensically examine the evidential weight being offered before making a judgement. This detail often seems to be conveniently overlooked by those who rely heavily upon the credibility of attribution studies. Such studies carry a great deal of scientific kudos, but one has to wonder what a good lawyer could do in a courtroom.”

    In other words, I say that the attribution studies are no better than the models they are based upon, and nobody can accuse me of being blind to the models’ limitations. I return to this point when I discuss Professor Otto’s recent proclamations:

    Friederike Otto, What’s Your Game?

    First, I quote Otto:

    “The Pacific Northwest 2021 heatwave is still rare in today’s climate, yet would be virtually impossible without human-caused climate change. As warming continues, it will become a lot less rare.”

    Then I say:

    “Subject to the usual caveats regarding the uncertainties in climate models and the statistically dubious manner in which uncertainty is treated when such models are handled as ensembles, there is nothing wrong with the above statement…”

    These are huge caveats that shouldn’t be forgotten, and I assure you that I haven’t. Climate modelling is a black art and a lot of epistemic uncertainty can be swept under the carpet when ‘tuning’ to fit the reality. The point I was making in the Kentucky case is that they have a model that doesn’t even fit reality, and yet they are carrying on as if they do.

    Liked by 1 person

  18. Mark,

    The NOAA’s take on the lack of warming compared to other parts of the contiguous US is as follows:

    “Hypothesized causes for this difference in warming rates include increased cloud cover and precipitation, increased small particles from coal burning, natural factors related to forest regrowth, decreased heat flux due to irrigation, and multidecadal variability in North Atlantic and tropical Pacific sea surface temperatures.”

    In other words, they don’t know. It’s just not in their models and, as Richard points out, these models don’t do local very well. Suffice it to say, they are not putting it down to a lack of UHI effect, but then they wouldn’t, would they? In the meantime, here is another graph to ponder:

    A Kentucky geologist looks at this and sees changes in line with predictions. I look at it and I see models systematically over-estimating.

    Liked by 1 person

  19. So climate science puts an ‘anthropogenic component’ in its climate models, which always run too hot.

    It then takes it out again as an attribution test, and says ‘aha! modern warming is all the fault of humans’. Why should anyone be impressed by that? They never put a natural warming factor into their models, so no other result was possible.

    Like

  20. dfhunter,

    Thanks for that. Who are these ‘experts’ who are referring to it as a 1 in 1,000 year rain event? This is so patently untrue.

    Like

  21. Speaking of modelling:

    “Trillions of dollars at risk because central banks’ climate models not up to scratch
    Climate research finds modelling used cannot predict localised extreme weather, leading to poor estimations of risk”

    https://www.theguardian.com/environment/2022/aug/10/trillions-of-dollars-at-risk-because-central-banks-climate-models-not-up-to-scratch

    “Trillions of dollars may be misallocated to deal with the wrong climate threats around the world because the models used by central banks and regulators aren’t fit for purpose, a leading Australian climate researcher says.

    Prof Andy Pitman, director of the Australian Research Council’s Centre of Excellence for Climate Extremes, said regulators were relying on models that are good at forecasting how average climates will change as the planet warms, but were less likely to be of use for predicting how extreme weather will imperil individual localities such as cities.

    The concerns, detailed in a report in the journal Environmental Research: Climate, were underscored by the Australian Prudential Regulation Authority’s release on Monday of its corporate plan 2022-23. Apra plans to “continue to ensure regulated institutions are well-prepared for the risks and opportunities presented by climate change”.

    But Pitman said regulators were still ill-equipped to assess the risks and to regulate the ability of banks and other institutions to cope with them.

    “Without a shadow of a doubt, we’re overestimating the cost of climate change in some areas and grossly underestimating it in others,” Pitman said….”.

    Liked by 1 person

  22. Mark,

    Prof Andy Pitman says:

    “If you’re going to throw billions or trillions of dollars around, you need to ensure that you’re getting the right scientific advice on how to interpret the climate information.”

    We couldn’t agree more.

    Prof Andy Pitman says:

    “I think that’s a no-brainer.”

    Yes, you would think so, wouldn’t you?

    Of the flood-prone Hawkesbury River near Sydney, Prof Andy Pitman says that it would flood:

    “…again and again and again. You don’t need climate projections to say there’s a vulnerability there.”

    Absolutely.

    But what I don’t understand is why the fact-checkers at the ISD and the BBC have not come down on Andy like a ton of bricks. But wait, I see he works at the Centre of Excellence for Climate Extremes.

    So it’s, Wayne’s World, party on dude.

    Liked by 1 person

  23. We have another “1000-year event ” in Death Valley:
    https://www.theguardian.com/us-news/2022/aug/10/death-valley-floods-climate-crisis
    “Recent severe rains in Death Valley that flushed debris across roadways, damaged infrastructure and carried away cars are being described by meteorologists and park officials as a once-in 1,000-year event”
    But then there is this:
    “While the storm did not break Death Valley’s all-time record for daily rainfall, it did break records for this time of year, as August generally produces just a tenth of an inch of rain.”
    If the rainfall did not exceed the all-time record it is unlikely to be a 1000-year event. More info here:
    https://www.latimes.com/california/story/2022-08-06/as-death-valley-dries-off-from-near-record-rains-some-see-fingerprints-of-climate-change
    “Rainfall totaling 1.46 inches was recorded at Furnace Creek Visitors Center on Friday, surpassing the Aug. 5 record of 1.10 inches set in 1936 but falling just short of the park’s heaviest rainfall of 1.47 inches on April 15, 1988, said Brian Planz, a meteorologist with the National Weather Service in Las Vegas.”
    Records began in 1911 so there are 112 years of daily rainfall data. It has been some time since I carried out a flood frequency analysis but you can look at the maximum annual values and make a reasonable estimate without carrying out a detailed analysis. With two annual maximum events of about 1.46 inches in 112 years, the August 2022 rainfall would have a return period of about 1 in 50 years. Just common sense really.
    So where did the 1 in 1000 year come from? If they are basing it on a frequency analysis of the annual August 5 rainfall for that specific day, it would be totally contrary to standard practice. Using that methodology, every large rainfall event would have a wildly extreme return period. Anyway, a 1 in 1000 year flood sounds more scary than 1 in 50 and fits the narrative better.

    Liked by 1 person

  24. Potentilla, from the Guardian article:

    “Daniel Berc, a meteorologist with the National Weather Service Las Vegas, described the deluge as a historic “1,000-year event”, with a 0.1% likelihood during a given year.”

    It justifies the claim with a link to this:

    “Death Valley Experiences 1,000 Year Rain Event”

    https://www.nps.gov/deva/learn/news/death-valley-experiences-1-000-year-rain-event.htm

    “…”The heavy rain that caused the devastating flooding at Death Valley was an extremely rare, 1000-year event, says Daniel Berc, meteorologist with the National Weather Service Las Vegas. “A 1000-year event doesn’t mean it happens once per 1000 years, rather that there is a 0.1% chance of occurring in any given year.” …

    …“Death Valley is an incredible place of extremes,” said park superintendent Mike Reynolds. “It is the hottest place in the world, and the driest place in North America. This week’s 1,000 year flood is another example of this extreme environment. With climate change models predicting more frequent and more intense storms, this is a place where you can see climate change in action!” ”

    A not unreasonable explanation of what is meant (by them at least) of a 1 in 1,000 year event, but as you point out, if they’re happening roughly once every 5 years, then that doesn’t really fit with the claim. Given the hype in the rest of the article (both articles), it looks more like propaganda to me.

    Like

  25. The definition given for the 1 in 1000 years flood is correct but it doesn’t change anything. To make such a determination you can only approach it in one of two ways: Bayesian or frequentist. The frequentist approach would be to take weather records and from those determine the likelihood of reoccurrence after an event. In this case, until recently historical data suggest there would only be a 0.6% chance of reoccurrence within 5 years. The fact that it has actually happened after only 5 years would then be highly suggestive of a change to the basis of occurrence and at some stage the new data would force a re-labelling of the flood severity. They wouldn’t want to do that, however, because they would then lose their headline.

    For there to be a Bayesian basis there would have to be a model available that predicts probabilities based purely upon what is known about causative factors. In this way one could make a prediction even for events that have never happened before.

    In this case it is not at all clear what basis is being used. For supposedly rare events, there isn’t going to be any good data upon which to form a reliable frequentist basis. If it is a Bayesian basis then what model is being used? If anthropogenic influences are included in it to predict a 0.1% annual occurrence then that model is highly likely to be wrong. Besides which, at no point does he say that we ran two models — the one without anthropogenic influence predicted a 0.1% annual occurrence likelihood but the one with influence predicted what we are now seeing.

    My guess is that he is attempting a frequentist argument, something along the lines of ‘we haven’t seen anything like this for about a thousand years and then three of them happen in quick succession so something must have changed’.

    Liked by 1 person

  26. Years ago many skeptics laughed at the huge focus climate fraudsters were placing on ” communication”. Boy we missed the implications of the liars’ great march through media.

    Like

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