We are keen to receive review comments for our new draft paper which is now available for open peer review here.
Ole Humlum: State of the Climate 2024
This report on the state of the climate in 2024 has its focus on observations, and not on output from numerical models. The observed data series presented here reveals a vast number of natural variations. The existence of such natural climatic variations is not always fully acknowledged, and therefore often not considered in contemporary climate conversations.
Global average surface air temperature for 2024 was the highest on record for all databases considered in this report. The years 2023 and 2024 were both affected by a warm El Niño episode. Towards the end of 2024 the most recent El Niño episode declined.
Submitted comments and contributions will be subject to a moderation process and will be published, provided they are substantive and not abusive.
Review comments should be emailed to: harry.wilkinson@thegwpf.org.
The deadline for review comments is 4 April 2025.
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Reviews
John McBratney, Telecommunications Engineer, Retired. Lancefield Victoria, Australia
Section 2. Ten Facts about the year 3034
There are several references in Section 2 that state temperature changes are due to Le Nino or La Nina “episodes. To the non-technical (in this field) these statements are without explanation and may therefore be discounted as “opinion” by unbelievers. I think it would be useful to provide a succinct explanation of both El Nino and La Nina effects. OK found it p 35. Perhaps locate it earlier so the reader knows what is being referred to.
As an engineer I understand what a Fourier analysis is but most readers would not. A short non-technical description would add weight to the conclusion in most reader’s eyes.
Section 3. Air Temperatures
An interesting analysis of temperature measurement locations and methodologies. This shows how incorrect the global warning pundits really are, they take no notice of such variations and most importantly of accuracy, resolution and precision, fundamental scientific and engineering issues. I suggest most of the loud climate catastrophy groups do not even understand the terms. A very useful assessment. A significant comparison is that most climate catastrophy pundits use “models” not hard measured parameters. Outstanding veracity of the Humlum method.
A note on the Contents: It would be of assistance to the reader to note page numbers for each contents heading. The Contents is quite intense and sometimes hard to find exactly where the reader is. I found I was not sure which section I was reading when noting comments.
4. Atmospheric greenhouse gases
Again measured figures show actual trends, no unverified “models”. Water vapour is the most important of greenhouse gases because of its absorption spectrum and higher concentration than CO2, again measured values, not model based guesswork.
5. Ocean temperatures
Noting sea temperatures are well ahead of global air temperatures and further ahead of atmospheric CO2. Not the other way round!
Global ocean average temperatures to 1900
Global ocean average temperatures to 1900 m depth
Regional ocean temperature changes temperatures 0-1900 m depth
Sea-level from satellite altimetry
Nicely put that it is useful but can be contested due to the need to use models, this is not the case with direct measurements and is a fundamental basis of this paper.
Sea level from tide-gauges
A nice description of land based sea level measurements. Few readers would be aware of the inherent movements of land levels and the explanation is excellent, most interesting that there is a location in Denmark that is stable, Korsør.
The disparity between measured and modelled sea levels tends to put doubt on all modelling in my view, how can one show the modelling software has included all aspects and included them correctly, when modelled result disagree with carefully conducted actual measurements?
Precipitation
Interesting sources/causes of precipitation, previously not widely known I suspect. The recorded data over 1980 to 1925 puts the lie to climate fanatic’s claims of increased rain and storm periods – hard data again!
Accumulated Cyclone Energy
Again actual data contradicts the fanatics, the document says “Existing records do not suggest any abnormal cyclone activity in recent years”. Current fanatic report try to say the opposite, that cyclones are increasing in frequency and intensity. Further the report states data records are too short to draw firm conclusions
Summary for 2024
Individual topic summaries are logical and based on measured data and are FACT. A marked difference to so called data issued by climate fanatics. The miniscule effect of CO2, compared to that of H2O should be more widely spread. This paper states “the global climate has remained a quasi-stable condition for millions of years”. Based on hard measured data how can climate fanatics disagree? The last sentence says it all: “Our world should consider focussing on real and much more pressing problems than a fictional climate crisis”
My Conclusions
The first most obvious conclusion from reading this heavily scientific technical paper (see suggestion on this aspect below) is that all results and conclusions developed therein are the result of actual physical measurements and are not the result of some sort of ill-defined software based model or models (they are all different anyway). This paper’s conclusions are based on ACTUAL data inputs thus the they cannot be disputed by the usual arguments used by climate fanatics.
This fact is a fundamental aspect of the paper and makes it one of the most useful documents on climate available anywhere today.
Regarding the conclusion stated that climate fanatics are naïve, I consider, in the light of this paper, that they are worse than naïve, they are not far short of criminal in that absolutely huge amounts of generally public money has been expended upon a non-existent problem for primarily vested financial interests.
Accordingly, I suggest that this document be made available to all politicians. The one problem in this suggestion on its own is that the document is too complex and so highlytechnical that very few average persons, intelligent or not, would endeavor to read it. I read it all.
My further suggestion therefore is that an appropriately qualified technical team be charged with producing a “general public readable” précis. Such a précis should capture the salient points of the various natural event’s that have an effect upon global temperatures and climate. Such an easily understandable document, based firmly upon actual measured data, thus it cannot be criticized from any viewpoint, would be a very powerful force against the world’s climate fanatics and would be a solid basis for government policies on energy matters.
I fear that if such an easily understandable précis is not produced this most valuable work of Ole Humlum will be largely wasted as no one in any sort of political power position will bother to read it.
Chris Harman
Congratulations. A most lucid and detailed review. Only one significant comment on matters that I think would improve the content.
Figs 24a and 24b
These give a most interesting analysis of water vapour at different altitudes. I was very much looking forward to the same information and associated commentary for CO2 (and possibly also for CH4) but there was nothing there. I think that this would be an important addition.
Other than the odd typographical error, this is my only comment.
Dr Maurice J Perks
Ole Humlum: State of the Climate 2024 paper.
I like the style of the paper and how it is segmented into the categories it covers.
I like the analysis segment of 10 years, but the analysis does not stop 10 years ago; it goes back to older times to establish trends.
The focus on variability drawn from these trends is interesting. This variability is due to natural variability and the accuracy of the measurements.
For me, too little is made of Section 4 Atmospheric Greenhouse Gases. No real conclusions are drawn or offered as to why water vapour is more important than CO2 in terms of climate variations. I’ll cover this in a moment, well, why I think it’s more important than the paper states.
I really do like from Summing it up.
The global climate system represents a multifaceted system, involving sun, planets, atmosphere, oceans, land, geological processes, biological life, and complex interactions between them. Many components and their mutual coupling are still not fully understood or perhaps not even recognised.
Personally I am a great believer in the effects, known and often unknown of Dynamic Complexity (see note pushing this just illustrating interest Solving the Dynamic Complexity Dilemma: Predictive and Prescriptive Business Management: Answering the Need for a New Paradigm | SpringerLink). It is the interactions of minor effects that cause changes, and today, as the paper concludes, we are focused on CO2 and ignoring all the interactions that may be causing natural or unnatural changes. It is like seeing a rural scent in black and white.
Jim O’Brien
1. The 10 facts, particularly #1 and #2, while trying to be brief, don’t say enough in my view: “highest on record” is a dangerous statement if not qualified in context, and explained for example as 0.15C rise per decade, that is only 1.1C rise by 2100. Also even the higher rate of sea level rise means only 25cm rise by 2100. The oceans certainly are not “boiling”!
2. Wherever 1979 is mentioned (start of satellite era), it could be good to put it in the context of global cooling from 1948 to 1979!
3. The various land-based temperature databases are so riddled with “adjustments”, that it is quite difficult to be precise about global average temp. Also the UHI effect is another significant source of error. In my view satellite temperatures are far more reliable. I’ve also previously mentioned to Ole about possible commentary on the Copernicus data (of which I am very suspicious), much beloved by the warmists.
4. I am intrigued by the several Fourier frequencies of 3.6y, 5.6y, 11.7y, etc. Nicola Scafetta gave us a lecture on the impacts of planetary frequencies, but these varied from 9 years upwards. There must be underlying secrets yet to be discovered!
5. Overall, I fell the report could be more effective if cut back in length, reducing the number of diagrams, making the really important key messages even clearer.
Will Bates
Small points:
(1) I understand that the averages showing warmer arctic near-surface air temperatures reflect warmer night-times, unchanged day-times. If that’s true, a line about time-of-day there might be nice.
(2) For future reports, I’d consider bumping up precipitation variability on the important list. This came up in January with respect to the Los Angeles fires. It’s a natural feature of California’s climate but apparently volatility has been on a secular increase over the last 100 years or so.
Pavel Kalenda
Dear Ole Humlun,
your „State of the Climate 2024“ report is very nice and complex.
I have no remarks or corrections of your results or data, but I have only 3 notices:
1) To the Fig. 17 – The temperature difference between satellite observations (QC1) and surface stations (QC2+QC3) show that during El-Niňo periods (1997-8, 2009-10 and 2023-4) are anomalous temperature in atmosphere from satellite measurements higher than from surface measurements. It means that the source of thermal anomaly is not below or on the surface, but in the atmosphere. The 2023-4 anomaly is evidently connected with Hunga-Tonga volcano eruption in December 2021. During the 2022, the enormous volume of water vapour was spread only in the atmosphere above southern hemisphere, but in 2023 is moved above northern hemisphere too. In the 2024 started the decrease of the vapour in the south and now is visible the decrease of the vapour in the north. Next Figure of satellite measurement of water content in the atmosphere is copied from the paper by Gerald Ratzer (gerald.ratzer@mcgill.ca) and it prove that the increasing of water content in the atmosphere after Hunga-Tonga eruption led to the anomalous El-Niňo event, which is now at the end.
Fig. 1 – GIStemp development 2014 – 2024 and water content in the upper atmosphere after Hunga-Tonga volcano eruption in 2021 (according to G. Ratzer 2025)
2) To the Fig. 46 – The AMO index correlates well with the eccentricity parameter of the orbit of Jupiter (Fig. 2), which has average period of 60 – 62.5 years.
Fig. 2 – AMO index 1856 – 2023 and eccentricity of the Jupiter´s orbit.
When the eccentricity of Jupiter´s orbit increases, the Jupiter´s rotational momentum decreases and it is spread among other bodies of Solar system (Sun or Earth are not exceptional). Therefore the Earth´s atmosphere (oceans and solid earth) rotation increases. The air movement in the mid-latitudes has west – east direction, polar vortex is increasing and the cold arctic air is concentrated above poles. Since 2020 the rotation of the atmosphere is slowing down, the air movement in the mid-latitudes has N-S and S-E direction (with sudden changes), polar vortex is breaking up and the dry cold arctic air is spreading to the mid-latitudes as well as the dry desert air (lecture by Piers Corbyn in 2018 in Porto – https://www.portoconference2018.org/ )
3) The changes of the air movement above Central Europe was documented by Kalenda and Šír (in the attachment) by the sum of “winter” or “summer” synoptic situations between 1946 and 2019. The number of “summer” synoptic situation is higher than average during the increasing period of air (ocean, LOD) rotation, i.e. 1975 – 2007. For example Ap3 situation (anticyclone traveling from Shetland across the North Sea to the southern Carpathians) has almost 10-times higher number of occurrences in 90. then in 60..
Fig. 3 – Time evolution of the relative frequency of the synoptic situation Ap3 (anticyclone traveling from Shetland across the North Sea to the southern Carpathians) in the period 1946–2019 and the fitted harmonic function – time derivative of the eccentricity of Jupiter’s orbit with a period of 62.5 years (black line)
Earth heat exchanger works in different way during increasing of the Earth´s rotation and during of the Earth´s rotation decreasing periods. That is why the changes of orbital rotation period of approx. 60 years are well visible not only in the solar activity, but directly in the meteorology parameters on the Earth.
Ian Plimer
What is never considered is heat added to the oceans from mid ocean ridges, off axis volcanoes and exothermic reactions from seawater circulating through the upper 5km of the oceanic crust. There is absolutely no credible data on this and it would be good to see Prof Humlum mention this when he writes about uncertainties.
Dr Hessel Voortman
Page 54; in the list of causes 1 through 4, I would split item 1 in meteorological effects (wind and air pressure) and astronomic effects (tides). They are fundamentally different
· Page 54; the suggestion that it is mainly 3 and 4 that drives the concerns. It may be too much detail for this report. But I know publications that insufficiently correct for multi-year tides and thus report an acceleration of sea level rise which is in fact a tidal effect (an example is Steffelbauer et al.)
· Bottom of page 56; should sattelite data be corrected for GIA? Consider that GIA changes the basin shape/depth, it has a real influence on sea level that in my view should be/could be monitored by satellite
· Page 57 (and other places); like prof. Humlum I am not a native speaker, so you will be the final judge in this matter. However, I think the phrase is “time will tell”; not “time will show”. The phrase is used several times
· Page 60; the Oslo picture is absolutely great, although embarassing for the people who prepared the projections
· Page 61, second paragraph. I assume prof. Humlum is referring to the projections on the NASA sea level projection tool. They do not show a sudden increase in 2020. Rather, the projections are given in steps of 10 years, the first being 2020. Like prof. Humlum, I have found that a comparison of levels is not very informative (yet). However, rates are also reported by the projection tool. Rates in 2020 can also be established from data (https://journals.open.tudelft.nl/jchs/article/view/7068). Doing so reveals a profound discrepancy of observations and projections.
When you look up my paper, you will see there is an additional link to a discussion paper. That was published only this week (with a closure by myself); observing the fierce response, I assume I must be right 🙂 (taking FLAK….)
· Third paragraph: the step change is not there, as I explained above. Prof. Humlum assumes that the observations were included when preparing the projections. I sincerely doubt that they are. See the attached paper by Kopp et al. that gives the background of the projections. In addition to reading this paper, I downloaded the source code of the model. My conclusions are preliminary (so it may be wise to ignore them in this year’s report) but I find that the starting year is a simple input parameter and that sea level is calculated with respect to the chosen reference year. Therefore, by definition, there is no discrepancy in 2005 and a growing discrepancy going forward
· Fourth paragraph: see previous point. Adding to that: the previous generation of projections had 1990 as the base year with the same definition (rise in base year = 0 m); at least this was the case in the Netherlands. The discrepancy mentioned by prof. Humlum was becoming apparent (and people in the Netherlands were becoming increasingly anxious when I pointed that out). Moving the base year to 2005 solved the problem is my (rather cynical) conclusion. But as I said above; a comparison of rates clearly and very rapidly shows the discrepancy