Maybe only 15% of CO2 increase since 1750 due to us – an unsettling result for those on board that luxuriously funded liner called the SS Climate Consensus.




The aim of trying to model climate by running simulations squillions of times when we know the system is crazily complex does seem absurd, and indeed liable to produce every possible kind of climate unless carefully tended by high priests who know what to look for to provide illustrations of the man-made CO2-driven climate crisis conjecture.

But we have other angles on the system which might provide more reliable guides as to our impact on it. One of these is the study of the cycles of atmospheric constituents as they move in and out of the airborne phase. These have been done for many elements and compounds, and typically they show high levels of uncertainty about the size and behaviour of sources and sinks. This is true for CO2 as well as the rest. But whereas the simulation models of linked differential equations for the whole climate seemed intrinsically doomed to farce and failure, the lifecycle studies of compounds such as CO2 are surely susceptible to ongoing improvement through increased quality and quantity of observations.

A recent paper by Hermann Harde of the Helmut-Schmidt University in Hamburg has rekindled my interest in this area. The title of his paper is ‘What Humans Contribute to Atmospheric CO2: Comparison of Carbon Cycle Models with Observations’ , and it can be downloaded free of charge from the link.

In a nutshell, he insists that human produced CO2, whether from land-use changes or fossil-fuel consumption, has to be treated alongside ‘natural’ CO2 since mother nature will treat a given molecule type the same, regardless of its origin. This is in contrast to the IPCC which has claimed that human-produced CO2 is accumulating in the atmosphere, and that almost all the increase in recent decades is due to us: ‘With a very high confidence, the increase in CO2 emissions from fossil fuel burning and those arising from land use change are the dominant cause of the observed increase in atmospheric CO2 concentrations.’ (AR5,

Harde’s analysis leads him to conclude that CO2 residence times are the order of a few years, and that these times apply to CO2 from any source. His flow model is basically the swimming-pool one as used by Salby, in which the rate of change of the amount of airborne CO2 is given by the difference between the flux into the air, and the flux out. He develops that further, and makes frequent comparisons with observations. He also examines, item by item, several assertions made in IPCC reports in this area and finds them wanting. For example the above quote from AR5 is said in that report to be supported by 5 arguments. Harde examines each and finds them inadequate as supports.

His conclusions from his own modelling are quite dramatic:

1. the recent increases in CO2 can be explained by a single balance equation, and is the only method yet which does so ‘in complete conformity with all observations and natural causalities’;

2. the human contribution to the recent increases is relatively small, e.g. ‘as an average over the period 2007-2016, the anthropogenic emissions … donated not more than 4.3% to the total concentration of 393 ppm, and their fraction to the atmospheric increase since 1750 of 113ppm is not more than 17ppm, or 15%.’

Is this not an area deserving of more research? But how will it be funded given that the direction of it seems so unfavourable to ‘the cause’? And will the bells announcing a climate emergency of a different kind be ringing soon on board the Climate Consensus?


  1. Oh dear! you mean he has done some science and used some measurements. That will get him nowhere, except abused of course.

    I used to think that climate science would eventually be self-correcting. But that was naive because it is now not about science but power, politics and mega-bucks. Even some of those involved that we thought fairly reasonable have actually shown that they are either fully on the Kool-aid or so frightened to lose their sinecure, grants and pensions that they stay quiet.

    AND climate science as practised by the majority is not a science is it?

    Thanks for the link to the paper Mr Shade


  2. Of all the Articles of Faith of Global Warming, this is perhaps the most crucial to the continued acceptance of the theory and the one which is the most difficult to challenge because of the enormous complexity of the carbon cycle and the near complete absence of evidence of what actually happens to CO2 emitted from fossil fuels once it gets into the atmosphere. It’s impossible to trace the life history of an ‘anthropogenic molecule’ and compare it to the life history of a ‘natural molecule’. I’ve never really understood how the IPCC calculate the ‘airborne fraction’ of anthropogenic CO2, or how they deem the miniscule (by comparison) annual contribution to total atmospheric CO2 from fossil fuels as somehow putting the natural carbon cycle out of balance such that CO2 accumulates steadily – even though I’ve read explanations of it several times. It’s not exactly intuitive.

    What can be said with reasonable confidence is that the narrative that CO2 levels were 270-280ppm for millions of years, then they suddenly shot up to 400ppm in the last 150 years, almost entirely due to fossil fuel burning, is extremely suspect and based on just one data source – ice cores. There are plant stomata readings of CO2 which are as high as 350ppm, even exceeding possibly 400ppm, dating back to the beginning of the Holocene, but these are ignored in favour of the Antarctic ice core data.


  3. I agree with all you say , Jaime. Not least ‘near complete absence of evidence of what actually happens to CO2 emitted from fossil fuels once it gets into the atmosphere’. In a more sensible world, one not driven by panics and pressure groups, that is the sort of thing that should have been subjected to intensive and extensive observation and analysis. Who knows, maybe the edifice, for such I suspect it is no more than, of CO2 Panic Politics will crumble as and when such studies are made. The ‘Missing Sink’ was talked about in the 1970s, and deserves further attention.

    Liked by 1 person

  4. The Berne Model of CO2 was the real kicker for me in placing me firmly in the sceptic group. Up to then I’d been more or less lukewarmer.

    It offended everything I knew about chemical equilibria. How a trace gas, which is absorbed almost as quickly as it is emitted, can linger in the atmosphere for decades was simply incredible.

    CO2 production doesn’t worry me, because I believe that once we cut it back that the residue will erode away quickly. But it is important for alarmism that no-one believe that. It is necessary that our sins of today cannot be rectified in the future so that we have to act drastically now, and now wait and see and then act if we need to.


  5. Synchronicity strikes again. Kenneth Richard dug up some old papers yesterday which demonstrated CO2 was much higher than 280ppm in the past. This data has been quietly shelved because it does not conform to the narrative.


  6. Man at the Back, and Chester Draws, I feel your dismay. It has not so much been like science as like the gold rush in the Klondike at the end of the 19th century. One difference though is that the climate scientists and close hangers-on kept their rush going by constructing artefacts designed to keep the fever high, not least the hockey-stick plot, and the Stern report. It is as if the Klondikers were able to find ways to keep the price of their gold high, and their substantial efforts worthwhile. Sadly for them, they couldn’t and their rush was over after only three years or so. Sadly for us, the climate Klondike has been going on for decades and seems still to have legs.


  7. Jaime, that chap Kenneth Richard deserves a medal for all the work he does on bringing good science papers to the attention of the sceptosphere. Digging into the link you gave, I found Pierre Gosselin, owner of that site, had drawn attention to the Harde paper much earlier than me – 3rd July. Some useful comments, and the odd silly one, after his post as well:
    There is also somewhat similar work by Ed Berry earlier this month:

    Liked by 1 person

  8. Kenneth is a veritable mine of useful information, John. It’s very encouraging to see science slowly coming back to life in the field of climatology and meteorology and the consensus dogma start to be seriously questioned. This is how it should be. Trump cancelled his planned panel of expert climate sceptics. It won’t be needed if the current trend continues.


  9. Hans,

    “Harde is wrong. Period.”

    Roger Tattersall disagrees:

    “Hermann is right. The additional sunshine hours of the 80s and 90s dried out volcagenic soils which then emitted far more CO2 than volcanoes do directly into the atmosphere. This post I made in 2012 has some useful info:

    I personally have no idea who is right or wrong here, and I suspect we don’t really know enough to be confident either way, but it’s helpful I think not to make assertions that simply refute an argument without at least attempting to illustrate why.


  10. Well Hans, there sure will be a lot of people hoping that you are right and Harde is wrong. A lot is at stake here.

    I’m hoping to work through his stuff to get a clearer idea myself, but I would not sit on the edge of your chair waiting for me. There once was a time when I could spend several hours a day, several days in a row, digging into a single paper to check it out. Now I might manage an hour or so once a week if I don’t have too many distractions.

    I was planning to begin with an earlier paper from Harde in 2017 in which he made the 15% claim. A commenter called DMA on the NoTricksZone post I link to in my previous comment here has provided links to this paper and some follow-up on it (see: The 2017 paper is here: This is of interest because Kohler et al. purported to refute it, and Harde provided a detailed response to their points that was not published by the Elsevier journal involved. Thanks to DMA, here that is:

    If you can help me zoom in on some points that might save me some time.

    Liked by 1 person

  11. Thanks for that link to Tallbloke’s, Jaime. A good post, and followed by some highly informative comments. All in 2012. He thought back then that this was a widening crack in the AGW argument.

    Liked by 1 person

  12. Thanks for the link, And Then. Good to get a copy of that critical response to Harde (2017). I hadn’t noticed that in the et al of Kohler et al (mentioned in my previous comment) was to be found the name Ken Rice. I have added to it my reading stack, and hope to have something to say about it and the Harde papers before too long.

    In the meantime, I note Harde was not exactly impressed by the work of Kohler et al:

    ‘Köhler et al.’s Comment is devoid of concrete analysis. Its tenor is to inundate the reader with citations, a reiteration of the IPCC catalogue.
    Invoked to support sweeping claims, too many of the citations are of dubious significance to be addressed here. Rather than responding in kind, we focus on key claims of Köhler et al. and the purported evidence upon which they rely.’
    (see final link in my previous comment to Harde’s full response)


  13. Certainly in the last 100 years its pretty conclusive that rising CO2 levels are caused by human emissions. It’s true our understanding of the carbon cycle is not fantastic, but there is just no other credible source for the CO2. The question that is more important is what percentage of our emissions be absorbed by the oceans and biosphere in the future. I think Nic Lewis has recently built up a model for this to estimate a carbon budget for 1.5C and 2.0C temperature rises. I’m a little surprised this work has not gotten more attention.

    I also suspect that even ice core measurements of CO2 from the past have lots of uncertainties. Of course much of paleoclimatology is highly suspect.


  14. Revisiting my old bookmarks on CO2, I come across Prof. Zbigniew Jaworowski’s Statement written for the Hearing before the US Senate Committee on Commerce, Science, and Transport, March 19, 2004:

    “The notion of low pre-industrial CO2 atmospheric level, based on such poor knowledge, became a widely accepted Holy Grail of climate warming models. The modelers ignored the evidence from direct measurements of CO2 in atmospheric air indicating that in 19th century its average concentration was 335 ppmv[11] (Figure 2). In Figure 2 encircled values show a biased selection of data used to demonstrate that in 19th century atmosphere the CO2 level was 292 ppmv[12]. A study of stomatal frequency in fossil leaves from Holocene lake deposits in Denmark, showing that 9400 years ago CO2 atmospheric level was 333 ppmv, and 9600 years ago 348 ppmv, falsify the concept of stabilized and low CO2 air concentration until the advent of industrial revolution [13].”

    It would be useful if those who assert that the post industrial rise in CO2 – as recorded by examination of Antarctic ice cores in conjunction with Mauna Loa direct measurements – is 100% due to fossil fuel burning could provide a link to an authoritative source which robustly demonstrates that Prof. Zbigniew was wrong 15 years ago.


  15. Also, I’m wondering why this 2013 scientific study is still published and not withdrawn as it purports to demonstrate that the rise in atmospheric CO2 since 1980 lags the change in mean global temperature by 9.5-12 months and that atmospheric CO2 levels do not track emissions. Please indicate where the study is comprehensively debunked – and not just because one of the authors is Ole Humlum!


  16. I discussed the high CO2 levels during the Holocene inferred from stomatal frequency in fossil leaves with Keith Briffa. His objection to using this data was not that it wasn’t recording high CO2 levels, but that the plants grew in areas with overall localized higher CO2, like near bogs where methane was being oxidized just beneath the surface, contaminating the immediately overlying atmosphere with excess CO2. Leaves with low stomatal frequences are more likely to be preserved in lake sediments near such bogs giving a false impression of high overall atmospheric CO2 levels.
    I have no knowledge of the truth or otherwise of this assertion.

    Liked by 2 people

  17. Alan, That story you related says a lot about how hard the climatocrats are willing to contort themselves to rationalize away inconvenient data.
    Briffa literally had one tree support a global claim while ignoring fossils representing data from many years.
    Clearly the fanatical fundamentalism that energizes the consensus kicked in early.


  18. Well if ATTP says something is definite, history strongly indicates the opposite is probably the case.


  19. Hunterson. Keith was one of the most open-minded people I have ever had the privilege to call a colleague and a friend. When discussing using leaf stomatal indexes we were both out of our depth. I see no reason to doubt that local CO2 variations exist near locations where leaves can be preserved. The question always was whether such variations were sufficiently large to explain away past variations. Preliminary investigations around the UEA lake were inconclusive because the background atmospheric CO2 level had become so high.
    Of all the climategate people, Keith was an exception.


  20. Alan,
    Thank you for the insight into Keith Briffa.
    Your story supports what I have heard about him elsewhere. That he was a sincere and thoughtful man and diligent as well.
    My point, poorly stated, was that the bias towards the big GCM CO2 driven apocalyptic consensus view was even early on in this debacle deeply entrenched. After all, he was involved in identifying, if I recall correctly, the world’s most important climate proxy tree from Yamal. Which is quite the opposite way of looking at limited botanical proxies such as fossilized stomata that don’t support the CO2 driven apocalyptic consensus.


  21. On the subject of CO2 levels in the 19th Century, I’ve got some data on this in one of various Victorian-era science textbooks that I happen to have in my house. The particular book with this data is “Physiography: An Introduction to the Study of Nature” by T H Huxley published in 1885. Thomas Huxley was a famous scientist in the 19th century, President of the Royal Society for some years, and was nicknamed “Darwin’s Bulldog” for his advocacy of the Theory of Evolution. The word he invented for the title of the book, ‘Physiography’, does not seem to have subsequently caught on.

    The CO2 values given in the book, converted to ppm are:

    On the Thames at London, mean: 343
    In the streets of London: 380
    From the top of Ben Nevis: 327
    From the Queen’s Ward, St Thomas’s Hospital: 400
    From the Haymarket Theatre, dress circle at 11.30 pm: 757
    From Chancery Court, 7 feet from ground: 1930
    From underground railway, mean: 1452
    From workings in mines, average of 339 samples: 7850
    Largest amount in a Cornish mine: 25000

    The measurements above were carried out by Angus Smith, a Scottish industrial chemist, in the early 1860s using a chemical analysis method. For people outside the UK, Ben Nevis is a mountain in Scotland and the tallest mountain in the UK. Smith may be the only person to measure CO2 at the top of a mountain before Charles Keeling started doing it, using a new accurate method that Keeling invented, in the late 1950s at Mauna Loa. The top of a mountain is probably the best location to measure ‘background CO2’.

    In the 19th Century there would only be a minor interest in measuring background CO2, the main interest then in measuring CO2 levels would be to get some idea of pollution in urban areas (Angus Smith invented the concept of ‘acid rain’), and measuring the potentially dangerous high CO2 levels that can occur underground.

    Zbigniew Jaworowski’s estimate that the CO2 level in the 19th Century was 335 ppm actually ties up reasonably well with Smith’s Ben Nevis value of 327 ppm. So Jaworowski’s claim that CO2 was higher in the 19th century than in the early 20th century could indeed be valid – it all depends on how accurate Angus Smith was at measuring background CO2 using the traditional chemical analysis method.

    Another thing that can be picked up from Smith’s data is that the CO2 level in an urban area is at least 50 ppm higher than the background CO2 level, and that was back in the days when motor vehicles didn’t exist. So when some Green blob protest group like XR are demonstrating in the streets of London about keeping down CO2 levels, the CO2 level in that street might already be at, or even beyond, the ‘doomsday level’ of CO2 that they’re warning the rest of us about.

    Liked by 1 person

  22. If anybody is interested in seeing more details of Angus Smith’s CO2 data collected in the 1860s, it was published in a book called “Air and Rain” in 1872. The book is available as a free PDF download from this webpage:

    The Co2 measurements are on pages 49 to 62. CO2 is referred to as ‘carbonic acid’ in the book. The measurements cover two cities in England, London and Manchester, two cities in Scotland, Glasgow and Perth, and there are about 80 readings for rural Scotland including several mountains.

    The average for rural Scotland was 336 ppm in 1865. That agrees very well with Zbigniew Jaworowski’s estimate of 335 ppm for the 19th century.


  23. Based on the lack of integrity and rejection of science and data we see daily by the consensus, it might be useful to revisit the earlier techniques and reports regarding atmospheric CO2.


  24. Thanks for the link to that book Dave. Saussure in 1796 measured CO2 on Swiss mountains and found that many locations were over 400ppm, the highest being 557ppm the lowest 360ppm. 76 years later, Angus Smith chemically analysed air on Scottish mountains and found the CO2 concentration to be remarkably stable (unlike that in urban areas), with a mean of 336ppm. If both their measurements are accurate, we may assume that the concentration of CO2 in well mixed pure air declined from the 1790s to the 1870s. Even if we discard the earlier, more primitive, but very careful measurements by Saussure, the implication is that pre-industrial air contained CO2 at concentrations well above 280ppm.


  25. In response to Jaime:

    The idea of measuring Co2 in mountainous areas is probably a more common practice than I was suggesting it was in an earlier comment. Horace de Saussure’s results are included and discussed in the “Air and Rain” book on pages 42 to 47.

    Rather high Co2 readings do seem to be obtained in Switzerland. I’ve heard of a study by Duerst at Bern in Switzerland in the late 1930s which reported a mean Co2 value of 400 ppm, whereas a mean value of 310 ppm was being reported in the USA in the 1930s.

    It may be that the whole idea of ‘background Co2’ isn’t as straightforward as it is cracked up to be. The idea might be applicable to most of the world, but in certain countries you get significantly higher values in rural areas.


  26. I do often wonder Dave if carbon dioxide is as “well mixed” as we are told. The OCO-2 results appear to confirm that it is not.


  27. More observational studies on CO2 do seem to be highly desirable. As for the theoretical stuff, I’ve been taking a closer look at Harde’s and others’ work on modelling and my emerging reactions are that Harde’s model (and it is not exclusively his) has the big merit of simplicity and an easy match with important data sets, whereas the complicated confection of the Berne model does not do so well on either count and may even lead to absurd results when pushed a little. It might even be another hockey-stick, i.e. something contrived to match the hopes of the alarmed ones to find confirmations of their vision of CO2 as a master lever up there in the air. A role it does not seem to have had in the past. Nor for that matter, in the present. More on Harde’s and others’ work later, subject to my ever-lengthening task-list.


  28. Picking up on a point I made earlier about how Green protest groups probably don’t realise how high the CO2 level might be in the street they are demonstrating in, I notice Extinction Rebellion (XR) is carrying out a four day protest starting from today (Aug 30th) where they are occupying some streets in the Deansgate area of Manchester.

    Nobody seems to measure CO2 in urban areas in the present day, and the whole exercise of measuring CO2 using Keeling’s method seems to be much more under the control of ‘gatekeepers’. But a value is available for the Deansgate area in Angus Smith’s book on page 51, measured on Feb 10th 1864, of 578 ppm. The Deansgate reading was taken in foggy weather conditions, which tends to result in a higher CO2 reading (Smith reports that the average for Manchester streets in 1864 was 403 ppm in usual weather and 679 ppm in fogs). 578 ppm is obviously well above the present day background CO2 level measured at Mauna Loa (415 ppm average in May 2019).

    It’s difficult to estimate what the CO2 level in a city like Manchester would be in the present day compared with 150 years ago. A new source of CO2 now exists in the streets in the form of motor vehicles, but on the other hand, the ‘middens’ have gone. Middens, for people not familiar with the word, are a combination of a refuse heap and a dunghill, and these dump sites would occur every few hundred yards in a mid 19th century urban area. Angus Smith measured an average value of 774 ppm CO2 around the middens in Manchester in 1864. Thanks to the invention of the motor vehicle, refuse is now dumped outside urban areas, and human excrement and urine is now flushed away in toilets instead of being dumped on a midden.


  29. Climate is already a complicated piece of science even before factoring net increase of 0.01% in the composition of the atmosphere (from 0.03% to 0.04%) in CO2 levels. However, there are two undeniable facts that need to be factored into our brains: We are emitting 44 gigatonnes of CO2 every year into a sink contained in the atmosphere and the hydrosphere of 167,000 gigatons of carbon atoms, a ratio of 1:3800.

    With an atmospheric/hydrospheric CO2 half-life of 3 years, I do not think that what we are emitting is of any significance. Has anyone ever picked up this plain scientific truth?


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