Reassessing Model Projections for Hot Days from RCPs –

An Aussie Perspective

Dr B Basil Beamish

Hot Day Projections in Australia

At the end of 2015, the CSIRO and Bureau of Meteorology (BOM) released a joint technical report that contained climate model projections for hot days in various locations around Australia. The values are contained in Table 7.1.2 on page 98 of the report for three climate model scenarios, commonly called Representative Concentration Pathways (RCPs). These values are 20-year averages centred on the periods of 2020-2039 (2030 for RCP4.5) and 2080-2099 (2090 for RCP2.6, RCP4.5 and RCP8.5). Hot day model projection values for Broome according to these climate scenarios are contained in Table 1. Each of the model projections indicates a substantial increase in the average number of hot days for the rest of this century. The media most commonly report the higher values to raise the “shock factor” of their articles. Consequently, the general public and politicians are bombarded with what can best be described as disingenuous exaggerations. In isolation as presented in Table 1, there is no real visual context for these values particularly in relation to historical data.

Table 1. Projected average number of hot days (Tmax >35°C)
for Broome, with 10th and 90th percentile values shown in brackets
(CSIRO and Bureau of Meteorology, 2015)


2030
RCP4.5
2090
RCP2.6
2090
RCP4.5
2090
RCP8.5
Broome 87 (72-111) 95 (70-154) 133 (94-204) 231 (173-282)

The temperature records for Broome are publicly available through the Bureau of Meteorology website. The highest 20-year centred average number of hot days recorded for Broome since 1910 is 63.9 for the years 1944-1963 (centred on 1954) and the annual hot day totals have fluctuated from a high of 90 in 1945 to a low of 20 in 2000. In the most recent year, 2018, there was a total of 55 hot days for Broome, which coincidently happens to be midway between these two extremes.

RCP8.5 The Futuristic Thermal Armageddon or Just Living in Lalaland

The RCP8.5 model projection for Broome is plotted in Figure 1 as a continuation of the actual results from 1910 using the ACORN-SAT maximum temperature data set. The graph also includes the measured and model projections for Global CO2 concentrations.

It is clear from Figure 1 that the RCP8.5 model projections for Broome are completely unrealistic and the three years of additional data since 2015 confirms this, since the 20-year centred average number of hot days has already begun to fall below the 10th percentile limit for this scenario. It will require the number of hot days in Broome to average above 60 per year for the next five years for the trend to maintain the lower limit projected from the model. This scenario has occurred in the past, and therefore it will be what happens after this period of time that will be critical in verifying the projected trends from the RCP8.5 model.

Figure 1. Broome annual hot day totals and actual 20-year centred average trend compared to climate model projections for RCP8.5.

RCP4.5 The More Moderate Thermal Armageddon

The RCP4.5 model projection for Broome is shown in Figure 2. There is an initial dramatic increase in the average number of hot days that gradually decreases in the latter years of this century. The current trend of the 20-year centred average for Broome, including the three additional years since 2015, plots within the boundaries of this model. However, this trend is no different to that experienced in previous years on multiple occasions.

By 2030 it will become readily apparent whether this model is valid, as by then the 20-year average number of hot days centred on 2020 for Broome should have exceeded the previous highest value of 63.9 to stay within the 10th percentile limit (Figure 3).

Figure 2. Broome annual hot day totals and actual 20-year centred average trend compared to climate model projections for RCP4.5.

Figure 3. Broome annual hot day totals and actual 20-year centred average trend compared to climate model projections for RCP4.5 shown on an expanded scale from 2000 to 2050.

RCP2.6 Global CO2 Emissions Reduction by Human Intervention

The RCP2.6 model projection for Broome shown in Figure 4 is essentially the same as RCP4.5 up to 2030. However, in subsequent years there is a gradual decrease followed by a steady decline in the median projected value for hot days from about mid-century. Consequently, the validity of this model should also be apparent by 2030.

Figure 4. Annual hot day totals and actual 20-year centred average trend compared to climate model projections for RCP2.6.

Placing Model Projections into Perspective

A striking feature of Figures 1, 2 and 4 is that there appears to be no correlation between the Global CO2 Concentrations and the actual data for Broome from 1910 to the present day. Therefore, past observations do not support the future projections based on increasing CO2 concentrations.

Climate model projections need to be verified against actual observations before any confidence can be placed in the model results. This takes time. Nevertheless, accountability of model projections should be mandatory given the importance that has been placed on them for policy decision making. The average number of hot days projected for locations around Australia is a good working example for this type of accountability analysis. The hot days trend for Broome from 1910 to present day clearly shows that climate model projections for RCP8.5 are totally unrealistic. As each subsequent year of data becomes available the model projections for RCP4.5 and RCP2.6 can be compared against the measured hot days results. Indications are that by no later than 2030 both these models will be either validated or invalidated. This same accountability analysis can be applied to any of the other locations shown in the CSIRO/BOM report.

References

CSIRO and Bureau of Meteorology, 2015. Climate Change in Australia: Projections for Australia’s Natural Resource Management Regions, Technical Report, CSIRO and Bureau of Meteorology, Australia, 216p.

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53 thoughts on “Reassessing Model Projections for Hot Days from RCPs –

  1. “It is clear from Figure 1 that the RCP8.5 model projections for Broome are completely unrealistic”
    This article seems to be just an argument from incredulity.

    • Yes.

      However, I dont think any gcm has demonstrated skill at the regional or local level. I’m wondering exactly how they framed these projections for a single site when the resolution would not support such a point forecast.

      Seems an odd claim to make.

      What model would they have used..?

      • EVERYTHING is EXTREME now! We are living in the Epoch of EXTREME!!

        All because you drive an automobile, heat your home, cook your food, power your laptop, and light your home. Your EXTREME energy use has caused an EXTREME reaction from our silver spaceship in the sun.

        • Ah so, first the Holocene Climate Optimum, ….. now it’s the Extremeocene Climate Optimum coming to your neighborhood.

    • incredulity — in·cre·du·li·ty (ĭn′krĭ-do͞o′lĭ-tē, -dyo͞o′-)
      n. The state or quality of being incredulous; disbelief.

      The argument from incredulity is a logical fallacy that occurs when someone decides that something did not happen, because they cannot personally understand how it could happen.
      https://rationalwiki.org/wiki/Argument_from_incredulity

      Nick,
      Note the use of the of the past tense in the definition, “did not happen.” Those Broome hot days in 2090 or 2030 have not happened, and may never happen at that frequency.
      They only exist as possible states in a multiverse future of probabilities.
      Imagine Schroedinger’s Cat replicated many millions of billions of times over, all those happy little cats in their happy little boxes, all in happy superposition states — just waiting for the weak force to decay a radioisotope atom to end their life with a poison gas release.
      Now you are extrapolating those all states to a particular exact 1 state when that time arrives in the present – the NOW; the quantum-collapsed 1 state of observation. Good luck Mr Cat. That’s the Climate Model folly.

      That is not incredulous. That is logical skepticism in action. Being incredulous about the past is not the same as being skeptical of future prognostications. Understand that Mr Stokes, and you’ll understand why the models will always fail in climate predictions into decades into the future.

    • Nick my underlying argument here is for the models to be verified against the actual data. The institutions putting these out there should also be made accountable, just as I have to be as a professional engineer. There is a lot riding on these projections, particularly in terms of the decisions being made by politicians.

      • Basil,

        I believe you are just throwing Nick, Mosh, the IPCC, BOM and CSIRO into the briar patch.* The RCPs aren’t even “projections” let alone predictions, so the real, the probable and the actual outcome will mean – with perfect precision – absolutely nothing! Unfortunately ;-(

        *Where they were born and bred! (See, Br’er Rabbit)

      • As a professional engineer in 7 states, I could suffer legal consequences for actions involving ethics, errors, omissions, etc. There seems to be no accountability for those using climate models to support political agenda other than the election booth. Until calibrated and verified, the models are little more than computer games used to support the agendas of the funding source (my opinion). If a cooling world kills 20 people in the winter for every one saved in the summer due to weather extremes, who will be held accountable? This 20 to 1 ratio does not even include those harmed because of reduced growing seasons, food redirection to biofuels, those forced into energy poverty, etc.

      • They have just made themselves accountable … I don’t think they thought this thru.

        Let me try to explain, there is a confidence level each side of that brown line you can set (you will note the green data points only have a fixed range plus or minus from that centre line). So now on the projection you can add that confidence interval top and bottom .. hopefully you get that.

        Now you can numerically rate the accuracy of the model each and every year going forward as simply the number of sites that stay in the confidence levels versus those that outside it. Taking a model down to local level on that upswing projection I doubt it will last a couple of years before it’s accuracy is shown to be so bad it is unusable.

    • Given that global warming theory, and all of it’s many attendant predictions and supposition, DEMANDS a abject credulity, what exactly is unreasonable about incredulity as a guiding principle?
      Skepticism is the very essence of the scientific method.

    • I have downloaded the ACORN-Sat data from BOM, for the years 2011 to 2018. With 2030 only 12 years away here should be some movement.

      The results for RCP4.5?

      2011 -2018 548 days > 35C at an average 68 days/year.
      For 2011 to 2030 there should be 1740 days. The result means that for the next 12 years the >35C days would need to average 99/year. Not likely but we’ll see.

  2. Regardless of smooth-line projections from the RCP scenarios (I assume this was CMIP5 ensemble mean?), nature will intervene in man’s best laid plans.
    Strong negative cloud feedbacks will intervene.
    The major ocean cycles will intervene.
    The sun may intervene.
    A volcano or two may make an appearance.
    And missing heat will not hide in the deep oceans, it will be lost there.

    The best course of action on climate is no action.
    The best course of action on infrastructure is continued sound engineering and building codes.
    The best course of action on policy to to use the money (the money not squandered on useless CO2 mitigation projects) to build to those better codes. New seawalls. Better flood control dykes. New Bridges. More powerline interconnects.
    And the best course of action on climate science funding is to de-fund the Climate Cargo Cultists.

    Australian politicians should be far more worried about Chinese Imperialism than anything related to climate. Unless they relish the thought of learning Mandarin in Xe’s re-education camps.

  3. Oh look! More (yawn) models…

    Now we can argue about whose arithmetic is the scariest (not to be confused with actually tracking real data).

  4. Sorry, but after I got to “the CSIRO and Bureau of Meteorology” I went no further.
    No reflection on the author, only the sources.

    • Tim, I have heard this comment from many of my colleagues, but I feel it is best to use the public data where it is available irrespective of the adjustments that have been made in the past. From this point on there should be no adjustments and any systematic error introduced should eventually drop out. They can’t keep adjusting upwards forever or its game over. That’s why these graphs help to draw a line in the sand for final validation of the models.

      • Thanks Basil. It would be encouraging to think it was finally the end of those magical and secret homogenization adjustments.

  5. Basil, your excellent essay invites some interesting questions from the CSIRO and Bureau of Meteorology re their research, data analyses and peer review.
    Have you forwarded your findings to the heads of these institutions (perhaps with copies to selected Australian pollies and press)?
    If you have I’m sure WUWT readers would be very interested in their responses – or lack thereof.

    • Lank anything sent to Pollies at this stage is a dead duck as they are all in self-preservation mode with an election coming up and couldn’t care less about the state of the country let alone some critical appraisal of model projections. I am continuing to analyse each of the locations that is quoted in the report for completeness, but can only do this on a part-time basis. I run my own business so have to keep chipping away at this bit by bit.

  6. I have discovered that everyone who contributes to this blog in anyway imaginable no longer believes that carbon dioxide is a greenhouse gas, that you all deny that temperatures have been increasing, and that there have been no changes to the global climate in any way shape or form and that every single one of you has a stream of income from the fossil fuel industry. At least that is what others tell me after I have destroyed their position. What I want to know is who is holding on to my share. You see
    unbeknownst to me it turns out that I have been hired by this same dastardly is group of evil industrialist to refute all of the cold hard facts of global warming which have been proven beyond the shadow of any conceivable doubt. So who is holding out on me? I need a vacation.

    • No.
      Most here are beyond tired of the alarmism related to a trace gas increase.

      Warming, yes is happening.
      Some may be attributable to CO2 increases.
      The atmospheric CO2 increases are only loosely coupled to human CO2 emissions by all solid verifiable accounts. But much of it may be due to human burning of fossil fuels.

      But ask yourself Robert, Would ceasing burning of fossil fuels by 2050 really be in the planets’ interest? Given that the resulting billions of starving humans would then strip every tree and kill every animal to survive? Macron of France saw what a few ten’s of thousands of pissed off citizens could do with ridiculous climate change policy. Imagine that 1000 times over across the world.

      The only relevant scientific question regarding climate and CO2 is the sensitivity question. And the answer to that question by observation is increasingly not in the Alarmists’ favor by a wide margin.
      That is science. Not propaganda.

      MAGA

      • Did you not read the part of my comment indicating that I was considered part of the group here? Is my mind just totally gone or do some of y’all need reading lessons?

    • Furthermore Robert,
      To me it sounds as if you need some Xanax. Call it a vacation to Club Med-(i-cation).
      Don’t worry, be Happy.
      Everything will be okay.
      The planet will be okay.

      As for Mankind, we’re F#$&-ed, just as George Carlin said.
      But that has nothing to do with climate or CO2.

      • I guess that I should have added a sarcasm indicator to my comments. I can get rather intense at times. I grew up watching my grandfather instigate discussions between my father and his two brothers around the dinner table. I realized later that most people would classify these discussions as arguments. Though everyone ended up on the front porch laughing and having a good time.

        • “I guess that I should have added a sarcasm indicator to my comments.”

          Yeah, you probably should have, although I did think you were saying you were a skeptic.

          Once you post here for a while and people get used to your skeptic position, the sarc tag becomes unnecessary except maybe on special occasions.

    • Skeptics are a pathetic lot. They have this fond belief that time will prove them right. Time will prove them dead.

      The organisation of the believers is so much better. They have very effectively turned weather into Climate Change.

      Academia knows there is money in Climate Change. The doctrine has been passed on to teachers and they are indoctrinating the young.

      Who on this blog would recommend their children or grandchildren pursue a career in an industry related to coal like mining the stuff or burning it? If they do recommended it, how many would be confident their child or grandchild would follow the recommended career path?

      Given the certainty that coal will be a global fuel for at least two more generations, it is likely some of the highest paid jobs will be in mining and burning coal because it will need high wages to persuade the young to pursue a dead end career.

      • “Time will prove them dead. “
        Well, ain’t none of us getting out of here alive. That we all can be sure of.

        As for coal mining or any other industry in energy extraction… you seem to have an elitist attitude that it is someone else’s job to produce the oil to make the petrol for your car take you to your job, the pub, or the store and back. Or for the power plant to have the coal to make the electricity to keep your lights and AC on.

        – Maybe a good paying job really is just a good paying HONEST job?
        – Maybe not everyone can work in a big gleaming glass office buildings, sitting behind computer screens all day, if we all want to enjoy the things modern technology can provide?
        – Maybe you just want to off-shore all those “dirty jobs (…”related to coal like mining the stuff or burning it:) to Third World countries. Countries where there are no work standards, no child age limits, no safety gear, no environmental standards? so all those people of color (who are not your children) can give you the things you think you need for you and your children.

        -Maybe someone has to get their hands dirty?
        -Maybe soldiers, sailors, marines, and airmen (maybe your children) have to die to ensure those opportunities and freedoms?

        Dirty Jobs… indeed

      • RickWill,

        Reading your post again made me think of Charles Bronson, the actor, died in 2003. He starred in action movies and a few western movies with many big names in Hollywood.
        (I read about Bronson this past weekend after a was talking to guy on a bike trail this past weekend who I kept thinking could have been Bronson’s twin brother, it kept bugging me he looked like Bronson, so I read up on Bronson).

        I was very impressed with Charles Bronson’s bio.
        He was from a dirt poor family in Pennsylvania with a Lithuanian name, Bučinskis, which became Buchinsky in America, which he changed to Bronson for his acting career. He was the only one in his family to graduate high school in the 1930’s, but still he went to the coal mines for 3 years. Hard work. Then WW2 and the huge call for young manpower allowed him to enlist in Army Air Corps and get out of the coal mines. He earned a Purple Heart as a gunner on B-29s in the Pacific on bombing missions against the Japs. He obviously never looked back, and went into acting.
        By the time he died, a very successful family man and very wealthy actor.

        And yet he started out in the coal mines. Hard work.
        https://en.wikipedia.org/wiki/Charles_Bronson

        Maybe your children could be so lucky as to understand hard work in mines?

      • RickWill,

        Assuming I actually owned kids, which I don’t, because apparently you need to have sex first for that to happen, apparently, I will still play with your little thought experiment.

        Recommend to children? Yup

        Have same children listen to me? HAHAHHAHAHAHAHA

        A child wouldn’t take a parent’s advice even if the advice was to experiment with drugs and to shag lots without protection. What makes you think they are about to take sane career advice? 😀

        Also, if I had a daughter I would absolutely suggest she get into engineering. She would not listen to me of course, but many of the female engineers I work with openly confess that most of their male workmates are so paranoid about appearing sexist that getting what you want at work was insanely simple.

      • “Skeptics are a pathetic lot. They have this fond belief that time will prove them right.”

        Yeah? And what do Alarmist have? The very same thing, they are hoping time will prove them right.

      • RickWill- since every prediction made about the future of the climate has turned out wrong why do you think this one is right. i.e. The climate will blow up in a heat death unless we kill off 2/3 or more of the population by black listing fossil fuels.

  7. It seems clear to me when plotting those projections against reality that there is adequate proof that the ”projectionists” are hallucinating. If you can draw a genuine correlation with co2 in those graphs please explain it to me! The models seem to have as much value as a drawing from a child with a piece of charcoal.
    Do these folks actually get paid to turn out this stuff?

  8. Dr Basil, I may have some bad (or good) news about your Broome analysis.

    You seem to have used ACORN 1 for your calculations but the ACORN 2 dailies were made available by the Bureau of Meteorology a few weeks ago.

    ACORN 2 maxima for Broome have cooled the first half of the town’s 1910-2017 record (i.e. 1910-1963) compared to ACORN 1, and that in turn increases the rate of hot day occurrence over the past 108 years. I’m not going to replicate your hot day formulas, percentiles, etc, but a quick example …

    Broome 1910-1963 days equal to or more than 40.0C:

    ACORN 1 = 178
    ACORN 2 = 116

    Broome 1964-2017 days equal to or more than 40.0C:

    ACORN 1 = 243
    ACORN 2 = 234

    Percentage increase in Broome days equal to or more than 40.0C comparing 1910-1963 and 1964-2017:

    ACORN 1 = 36.5%
    ACORN 2 = 101.7%

    Yes, there’s nine fewer 40.0C+ days in the latter half of the 108 year record under ACORN 2 but that doesn’t detract from ACORN’s goal of establishing that Broome and Australia are warming rapidly. However, it might add to your point about Broome’s hot day trend since 1910 compared to future projections (if homogenised temps are to be used) .

    Incidentally, comparing Broome’s average annual max between 1910-1963 and 1964-2017, ACORN 1 warmed 0.31C and ACORN 2 warms 0.72C (raw warmed 0.23C). For Broome min, ACORN 1 cooled 0.10C and ACORN 2 warms 0.41C (raw warmed 0.06C).

    Anybody who wants to see how the bureau has rewritten Australia’s temperature history with ACORN 2 and increased the rate of warming should visit http://www.waclimate.net/acorn2/ where you’ll find charts, data and spreadsheet downloads for Broome and for all 57 Australian ACORN stations that were recording temps from 1910 to 2017.

    My analysis of the 57 stations shows that if again comparing the first and second halves (1910-1963 vs 1964-2017), the average maxima for Australia …

    ACORN 1 warmed 0.39C / ACORN 2 warms 0.49C / RAW warmed 0.32C

    And for minima …

    ACORN 1 warmed 0.51C / ACORN 2 warms 0.71C / RAW warmed 0.39C

    These are annual averages at the 57 long-term stations, not all 112 ACORN stations the bureau uses to calculate national temperature trends, so they’re not necessarily the same as what the official Australian data will be.

    Nobody in Australia yet knows about the ACORN 2 rewrite of Australia’s climate history because there’s been no media coverage. The bureau has indicated that ACORN 2 will be propagated through its website early this year.

    The bureau’s ACORN 2 report confirms that averaged across all the network’s 112 stations, Australia’s rate of mean temperature warming per decade from 1910 to 2016 increased from 0.100C in ACORN 1 to 0.123C in ACORN 2. That’s a 23% increase in Australia’s rate of mean warming per decade over the past 108 years.

    There could be some interesting political repercussions when the media hears about the ACORN 2 temperature rewrite and how Australia is getting hotter more rapidly than thought since ACORN 1 was released in 2012.

    And it’ll again show that homogenisation is the art of picking and choosing the non-climate adjustments you wish to include, ignore or scale according to your preferred interpretation of documented (and undocumented) weather station changes since 1910.

  9. pity the investigation…term VERY loosely used was so limited(intentionally) that the bom csiro didnt get exposed for the shams they are
    of course since csiro got the go for profit nod…little of trustworthiness emanates
    Bom just downright stuffed

  10. I’m madly curious about what the model projections showed for Broome in their *historical* runs, and how that compares to actual results (though ACORN 1/2 seems to have changed that radically). I’d be surprised if they demonstrated skill.

    Any sort of metric depending on absolute temperatures in a particular location may not be a good fit for models, since they don’t agree among themselves on what the absolute temperatures are. The only thing that GCMs have been demonstrated to do is predict the long-term anomaly trend, if your expectations are low enough.

  11. Imagine the panic such modelling would have provoked if they had been doing it in the 1930s and early 1940s.
    What they are basing their models on is insignificant compared to the rise between 1915 and 1945. It is unbelievable that they can be aware of what happened after the first half of the twentieth century and yet insist on causing global hysteria causing severe financial pressure on the least well off due to the rise in the cost of energy.

  12. I did not think that current models included terms for cloud behavior yet I ran across a paper comparing satellite versus models cloud cover. Do current models contain terms for cloud cover and just do a bad job?

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