Everyone swears the IPCC have proof, but still nothing from the AR5

The IPCC don’t have no evidence!

(All right, all right! Leave off with the double negative put-downs already!)

common arguments • interesting rebuttals • startling absence of proof


Looking at the recent geological (let’s say prehistoric) record then the exogenous inputs (mainly from volcanism) seem to have been low relative to historic exogenous inputs (mainly from agricultural soil organic matter breakdown and fossil fuel burning), which means that the two eras are not comparable and so conclusions drawn from one cannot be applied to the other.

Yet the IPCC does exactly that. They rip an isolated fact from its primeval context and claim it applies today. But it flies in the face of copious evidence and asserts that the global mean surface temperature (GMST) is determined by only a single factor: the trace gas carbon dioxide. For instance, on p. 50, the AR5 Technical Summary harks back 52 million years to inform us:


In several periods characterized by high atmospheric CO2 concentrations, there is medium confidence that global mean temperature was significantly above pre-industrial level. During the mid-Pliocene (3.3 to 3.0 Ma [mega-annum, million years ago]), atmospheric CO2 concentration between 350 ppm and 450 ppm (medium confidence) occurred when GMST was 1.9°C to 3.6°C warmer (medium confidence) than for pre-industrial climate. During the Early Eocene (52 to 48 Ma), atmospheric CO2 concentration exceeded about 1000 ppm when GMST was 9°C to 14°C higher (medium confidence) than for pre-industrial conditions.

We are to deduce that 1) high CO2 levels caused great warming in the past and 2) therefore they’ll do the same today. But no causal connection is described for 1), so deducing 2) is illogical. In addition, we hear four times in three sentences that the IPCC have “medium confidence” in this thesis, which demonstrates no confidence at all and emphasises the lack of causation. Overall, not a powerful prelude to demanding trillions of our tax dollars to battle the weather.

Preposterous narrative


Are you saying that the evidence of the past hundred years or so is unreliable that raised levels of atmospheric CO2 cause increased atmospheric temperature?

Yes, since the evidence indicates the exact opposite: the data clearly show that increased temperatures occurred before atmospheric carbon dioxide rose. This perhaps happened largely through outgassing from the ocean. The IPCC have not demonstrated a causal connection between atmospheric CO2 and warming, nor can they produce such evidence when asked. Temperatures have not consistently risen over the last 100 years and show much variation, though CO2 levels have risen almost monotonically. Early records are sparse but a narrative that ignores any temperature decline and claims in defiance of observation that CO2 rises before temperature does is preposterous and fraudulent.

Three plain atmospheric facts show clearly that CO2 does not dominate the surface temperature.


Mankind has of course contributed some of the airborne CO2, but how much, exactly? There are many studies, but two are in the same ball park: Dr Ed Berry, a consulting meteorologist with a PhD in physics, and the AR5 from IPCC (summarising other PhDs).

Dr Berry shows anthropogenic CO2 is 18 ppmv (4.4% of the atmosphere, or 0.141 × 1012 tons CO2). A paper, Human CO2 Emissions Have Little Effect on Atmospheric CO2 (pdf, 670 KB), was published last year in the International Journal of Atmospheric and Oceanic Sciences, concluding:

Human CO2 is insignificant to the increase of CO2 in the atmosphere.

The IPCC AR5 suggests an increase of about 113 ppmv in atmospheric CO2, stating that 240 GtC have accumulated in the atmosphere from 1750 to 2011 (AR5 SPM, p. 12). So 240 billion tonnes of carbon × 3.667 = 880.08 Gt CO2, or 0.880 × 1012 tons (trillion tonnes) — not terribly far from Dr Berry’s 0.141 trillion tons.

Even if carbon dioxide significantly raises the temperature, our responsibility for weather events is practically imperceptible and the IPCC can offer no more certainty of human influence than a sheer guess, as revealed in this summary from the AR5:

It is extremely likely that more than half of the observed increase in global average surface temperature from 1951 to 2010 was caused by the anthropogenic increase in greenhouse gas concentrations and other anthropogenic forcings together. The best estimate of the human-induced contribution to warming is similar to the observed warming over this period.  – (AR5 SPM, p. 17)

How warped, perverted and wicked that we find at the heart of the IPCC narrative of man-made warming an empty, meaningless paradox. The first sentence thinks it extremely likely that man-made warming was about 50% of the observed warming, but that’s immediately refuted by the second sentence opining that man-made warming was the whole amount of the observed warming. This frankly brainless logic offers a clarity of mind arising only in intellects needing prolonged, intensive pedagogy.

We have been assiduous during more than 15 years, yet wherever we look for the evidence that everyone else says the IPCC has written in its reports, we find nothing.


Radiation transmitted by the atmosphere, with wavelengths increasing from left to right. The red line shows where incoming shortwave radiation (left) gives way to outgoing longwave radiation (right). Click for the complete diagram.

At concentrations varying from about 10,000 ppmv to over 40,000 ppmv, and at 25 times to 100 times more abundant, water vapour’s influence towers over CO2, which at present is about 408 ppmv. By mass, there are 12.7 trillion tonnes of airborne H2O as both vapour and liquid, dwarfing the 3.2 billion tonnes of CO2. CO2 is only a quarter the mass of water and responsive to only a small fraction of outgoing radiation. In the diagram at right showing absorption by various gases at a range of wavelengths, where the grey bands in different rows overlap, then in the troposphere water absorbs the lion’s share of radiation. In total, CO2 stands little chance of intercepting photons before water gets them, and in the few wavelengths where it does stand a chance, there’s little energy available to be absorbed.


It’s not the atmospheric trace gases that dominate the world’s surface temperature, it’s water vapour—the IPCC say so. At different times, H2O is 500 to 2000 times more abundant than the man-made portion of CO2 and a molecule of water vapour absorbs more than 10 times the amount of incoming solar energy and outgoing long-wave energy than a molecule of CO2. This diagram shows the relative abundances of water vapour and carbon dioxide — both natural and anthropogenic. H2O outclasses CO2 in all departments.

The troposphere contains 99% of the H2O and around 80% of total atmospheric mass, which means it has 80% of the CO2. It seems highly unlikely that water vapour would be overwhelmed by the meagre quantity and puny radiative effects of CO2.

Click to enlarge.

The diagram shows the relative atmospheric abundances by mass of three gases: oxygen, water and the two interesting kinds of carbon dioxide, natural and man-made, in four disks. Our red oxygen disk at this scale is over a metre in diameter so we see only a portion. Oxygen in turn would be surrounded by nitrogen at about 4.4 metres in diameter, 3.7 times more massive than oxygen, and the whole atmosphere (5.1 m), over four times more massive than oxygen.

An arrow points to man-made carbon dioxide accumulated since 1750 — the teeny dot beside the green CO2 disk. I’ll shortly add argon to the picture and polish the arrangement, but at least now you can see it (I’ve been working on this erratically for months).

Still no evidence — incredible

The only evidence that higher levels of CO2 cause increased atmospheric temperatures comes from unverified climate models which are completely unreliable — not to mention that they don’t derive the warming from first principles, they’re told what warming to calculate. Actually, most sceptics say the models are false to the point of fraud. So do I. For the last twenty years the models have predicted rapidly rising temperatures and have always been wrong. The IPCC have reduced their projections further with each new Assessment Report.

Local variations in humidity over mere minutes can cause changes in forcing that far outweigh CO2 increases of the order of 120 ppmv over a century, while anthropogenic changes amount to less than 10 ppmv over 100 years.

The GMST is not controlled by a single gaseous factor but multiple complex systems. In the words of the IPCC (Third Assessment Report, TAR, ):

The climate system is a coupled non-linear chaotic system, and therefore the long-term prediction of future exact climate states is not possible.

A statement of good science missing from more recent reports. See more extracts from the TAR.


3 Thoughts on “Everyone swears the IPCC have proof, but still nothing from the AR5

  1. Cambridgedon on June 9, 2020 at 5:27 pm said:

    The CO2 is higher than it has been for 3 million years; then the sea level was 15-24m higher.

    If you are a geologist, read statements from these the UK and US geological societies.



  2. Richard Treadgold on June 9, 2020 at 5:44 pm said:

    I’m not a geologist, but those web pages are perfectly opaque; perhaps you might summarise them for us? If CO2 has gone up about 25% of nothing in the last few seconds, I mean 100 years (a trifling period against 3 million years), it means nothing. The temperature has risen, through the action of a little extra CO2, perhaps (here’s the best guess from the IPCC) 0.5°C. That’s undetectable. Nobody should be concerned about that. In New Zealand, the difference in average maximum temperature between summer and winter is about 15°C. So what? The sea level is still rising after the end of the last glaciation, but the rate of rise is not accelerating. Nothing to worry about.

  3. I’m having a bit of trouble understanding your argument, Cambridgedon. 3 million years ago was when the present ice age began. But if the atmospheric CO2-level back then was as high as it is now and the present CO2-level is already causing sufficient global warming to melt the polar ice-caps and the world’s glaciers, why did the planet enter an ice age 3 million years ago instead of shifting further away from one as the alarmists claim it is doing now? If the ‘CO2 control-knob’ really does control the global mean temperature, that’s what you would expect to happen, wouldn’t you?

    Also, if the sea level back then was 15-24 metres higher than it is at present with the same level of CO2, why was that? Again, if the ‘CO2 control-knob’ really does control the global mean temperature, you would expect the sea-level back then to be approximately the same as it is now, wouldn’t you?

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