Junk science of Climate Sensitivity and CO2 forcing

Principia Scientific Tim Ball | April 15, 2016

We recently published an article by Edward Hoskins entitled “The Junk Science Of A Supposed Climate Sensitivity Formula”. The author requested a review from PSI’s former chairman Dr. Tim Ball, which we pleased to be publishing below with extracts from the original article.

The diminishing influence of increasing Carbon Dioxide CO2 on temperature

The diminishing effect of CO2 on temperature

The temperature increasing capacity of atmospheric CO2 is small, but it is real enough.

The influence of CO2 concentration on temperature is known and widely accepted to diminish progressively as its concentration increases.

I understand that this is the generally accepted position about CO2 as greenhouse gas (GHG). I have yet to find or hear of any definitive proof that CO2 operates as a GHG, I have read much about rotating dipoles and other issues. I also heard the argument made some 20 years ago at a presentation in Calgary by a prominent skeptic that it was politically safer to say CO2 had a small greenhouse effect but it was so small as to be insignificant. I never agreed with this position and still don’t.

CO2’s effect diminishes logarithmically with increasing concentration. Both  Global Warming advocates and Climate Change sceptics agree on this.  IPCC Published reports, (TAR3), acknowledge that the effective temperature increase caused by growing concentrations of CO2 in the atmosphere radically diminishes with increasing concentrations.[i].

This information has been presented in the IPCC reports. However it is well disguised for any lay reader, (Chapter 6. Radiative Forcing of Climate Change: section 6.3.4 Total Well-Mixed Greenhouse Gas Forcing Estimate).

One of several deceptions about CO2 made by the IPCC to further their objective of proving their hypothesis is that CO2 is evenly distributed throughout the atmosphere. I knew that was wrong and was borne out by the recent results from the NASA satellite OCO2.


Other deceptions included the residency time of CO2 in the atmosphere, to support their argument that even if we stopped production now the problem would persist for decades.

There are other deceptions but you get the picture.

This is a crucial fact.  It is not acknowledged in the IPCC summary for Policy Makers.[ii].

The rapid logarithmic diminution effect is an inconvenient fact for Global Warming advocates and alarmists.

It is well understood within the climate science community.

It is certainly not much discussed.

This logarithmic diminution effect is the likely reason there was no runaway greenhouse warming caused by CO2 in earlier eons when CO2 levels were known to be at levels of several thousands parts per million by volume, ppmv.

The following simplifying diagram shows the logarithmic diminution effect using tranches of 100ppmv up to 1000ppmv and the proportional significance of differing CO2 concentrations on the biosphere.

psi 1

• Up to ~200 ppmv, is the equivalent to about ~77% of the temperature increasing effectiveness of CO2.  This level of atmospheric CO2 is essential to sustain photosynthesis in plants.

This level of CO2 or above is absolutely essential to maintain the viability of all life on earth.

The major objective of the research associated with the IPCC was to provide evidence that fit their hypothesis. The major one was to show that the pre-industrial level of CO2 was low. A few of us (Jaworowski, Beck) have written about this and been ignored even by most skeptics. I knew what was going on after 1983 when Wigley published his analysis of the approximately 90,000 19th century CO2 readings and set the pre-industrial level at 270 ppm. Here are a couple articles I wrote about the issue. There is no doubt in my mind that the the actual level was 365ppm.



Jaworowski’s papers. He was so good that the UN made him chair of the Chernobyl investigation.


Download  pdf paper 1.4 MB

I also worked with Ernst-Georg Beck who revisited the 19th century data and was viciously attacked, but, in my opinion was correct. His papers follow.


http://www.friendsofscience.org/assets/files/documents/CO2 Gas Analysis-Ernst-Georg Beck.pdf

• ~300 ppmv was the approximate level prior to any industrialisation, this atmospheric CO2 made the continuing survival of the biosphere possible, but only causing a further 5.9% of the CO2 Greenhouse effect.

• Following that a further 100ppmv, (accepted by the IPCC to be ~50% man-made in part), adds ~4.1% of the CO2 effectiveness brings the current level ~400 ppmv.

• CO2 at 400 pmmv is already committed and immutable.

• So CO2 has already reached about ~87+% of its potential warming effect in the atmosphere.

Thereafter the following 100ppmv tranches will give these percentages:

• 400-500 ppmv ~3.23%

• 500-600 ppmv ~2.64%

• 600-700 ppmv ~2.23%

• 700-800 ppmv ~1.93%

• 800-900 ppmv ~1.71%

• 900-1000 ppmv ~1.53%

So now at 400ppmv only a total ~13% of the effectiveness of CO2 as a Greenhouse Gas now remains even up to the level of  ~1000ppmv.

And any levels beyond 1000ppmv can have virtually no further warming effect.

It is reasonable to assert that the earth and its biosphere are still only marginally above a minimal level for survival.

When photosynthetic plants originally evolved on earth they did so in an environment of atmospheric CO2 at many 1000’s ppmv.  In the horticultural business plant growth is routinely enhanced by adding levels of CO2 in their greenhouses to be three times or more than that of the external atmosphere.

The average levels fro the last 300 million years is between 1000 and 1200 ppm. You mention the commercial greenhouse levels but there is the more valuable scientific evidence for research produced by Sherwood Idso and his son Craig. I highly recommend their web page.


The other important issue with increase levels of atmospheric CO2 plants use less water. This is primarily because the stomata are reduced in size.

Skeptical scientists and the IPCC publish alternate views of the reducing effect on temperature of the importance of CO2 concentration.  These alternates are proportionally equivalent but vary in the degree of warming attributable to CO2 concentrations.

The IPCC publishes the following views of the total effect of CO2 as a greenhouse gas up to ~1200ppmv.  In total they range in temperature from +6.8°C to +15.2°C and could give future additional warming between the current ~400ppmv level and the 1000ppmv level of in the range of +1.2°C and +2.9°C.

psi 2

It is important to note that the IPCC refer to this as the “climate sensitivity” of CO2. It is another of the contrived indices to advance the AGW hypothesis. It evolved from the problem that initially methane then CO2 were such small fractions of the Greenhouse Effect that they needed to exaggerate their impact so they produced the Global Warming Potential index.


John O’Sullivan can attest that every time they came out with a lower sensitivity number I emailed him with a “here we go again” message and saying we were heading to zero, it was just a matter of time.

Another important point, to further my point about creating science to prove there hypothesis fits here. When the upper limit of CO2 greenhouse effect due to saturation was introduced, and Steve Milloy at Junkscience was in the forefront of the issue, the IPCC proponents produced the positive feedback argument. This said that CO2 caused a temperature increase that resulted in increased evaporation that enhanced the greenhouse effect. Lindzen and Choi debunked the argument.


Other views have also been asserted both by skeptical scientists and CDIAC[iii]., the Carbon Dioxide Information and Analysis Centre.

What these different analyses show the is the amount of future warming that might be attributed to additional atmospheric CO2 in excess of the current level of ~400ppmv is going to be marginal.  Looking to the future in excess of 400ppmv, wide variation exists between the different warming estimates up to 1000ppmv.

A comparison between these estimates are set out below in the context of the overall ~+33°C total Greenhouse Effect.

This number was always suspect. In the early days it ranged from 31°C to 35°C. They assumed 15°C for global average and a world without greenhouse gases ranging from -16° to -20°C. I have never seen effective confirmation of the 33°C figure. Even if it is out by 1°C it changes the entire AGW claim. 

psi 3

This graph shows in orange the remaining temperature effect of CO2 that could be affected by radical worldwide global de-carbonisation policies, to maintain CO2 levels at the current 400ppmv and the appropriate warming that could result by raising the CO2 level up to 1000ppmv, according to each of these alternative postulates.

But some of the IPCC sourced data shows very large proportions of the temperature effect attributable solely to the currently existing levels and any extra CO2 up to 1000ppmv.

The concomitant effect of those higher levels of warming from atmospheric CO2 is that the proportion of the total ~33°C then attributable the water vapour and clouds in the atmosphere is displaced so as to be unrealistically low at 72% or even down to 54%.

It has to be questioned whether it is plausible that CO2, still a minor trace gas in the atmosphere, currently at the level of ~400ppmv, 0.04% achieves such radical control of Global temperature, when compared to the substantial and powerful Greenhouse Effect of water vapour and clouds in the atmosphere?

There are the clearly divergent views of the amount of warming that can result from additional CO2 in future.

But even in a worst case scenario, whatever change that may happen can now only ever have a marginal future effect on global temperature.  The logarithmic diminution effect leaves only a marginal 13% of the CO2 warming effect remaining.

Whatever political efforts are made to de-carbonize economies or to reduce man-made CO2 emissions, (and to be effective at temperature control those efforts would have to be universal and worldwide), those efforts can only now affect at most ~13% of the future warming potential of CO2 even up to the currently unthinkably high level of 1000ppmv.

So increasing CO2 in the atmosphere can not now inevitably lead directly to much more warming and certainly not to a catastrophic and dangerous temperature increase.

Importantly as the future temperature effect of increasing CO2 emissions can only be so minor, there is no possibility of ever attaining the much vaunted political danger zone target of less than +2.0°C by the control of CO2 emissions.

Global Warming advocates always assert that all increases in the concentration of CO2 are solely man-made.  This is not necessarily so, as the biosphere and slightly warming oceans will also outgas CO2 over the long term.

They achieve this through their definition of climate change as only those changes caused by humans. Of course, if you omit most natural causes and water vapour the result they claim is guaranteed. They ignore water vapour arguing g that humans produce it but in such small amounts relative to the amount in the atmosphere it is inconsequential. The problem is that argument negates their positive feedback claim. Variance of water vapour in the atmosphere and the effect of that on global temperature far exceeds the effect of CO2 in total let alone the human portion.

In addition CO2 concentrations have been shown to lag behind any historic temperature increase, rather than be caused by it.

They made all sorts of arguments about the lag time but the reality is it occurs in every record of any duration. Look at Beck’s estimate of the lag. The only place in the world where CO2 increase precedes a temperature increase is in the IPCC computer models. Remove that assumption and computer code and their claims are completely rejected. Their finding is also guaranteed by leaving out major natural causes of variation especially the Svensmark effect.

The recent IPCC report now admits that currently increasing CO2 levels are probably only ~50% Man-made. On the other hand it is likely that any current global warming and increased CO2, if it is continuing, is:

• largely a natural process

• within normal limits

• probably beneficial.

It could be not be influenced by any remedial de-carbonisation action, however drastic, taken by a man-kind.

In a rational, non-political, world that prospect should be greeted with unmitigated joy.

If it is so:

• all concern over CO2 as a man-made “pollutant” can be entirely discounted.

• it is not essential to disrupt the economy of the Western world to no purpose.

• the cost to the European economy alone is thought to be ~ £165 billion per annum till the end of the century. This does not include the diversion of employment and industries to elsewhere, where concern over Global Warming is not a priority.

• this is deliberate economic self-harm that can be avoided.

• these vast resources could be spent for much more worthwhile endeavours.

• were warming happening, unless extremely excessive, it provides a more benign climate for the biosphere and mankind.

• any extra CO2 is already increasing the fertility of all plant life on the planet.

• if warming is occurring at all, a warmer climate within natural variation would provide a future of greater opportunity and prosperity for human development, especially so for the third world.

The practice is to carry out only the cost portion of cost/benefits of any analysis. This is especially true of such studies as the infamous Stern report commissioned by the IPCC and any study done of alternate energies. I am not sure any cost/benefit analysis can be done now because government subsidies are so pervasive at so many levels that sorting them out is impossible.

If they did proper cost/benefits they would include the costs of cooler conditions because the increased adaptation costs to cooler because they planned for warmer, must be included.

If you think the climate science is rubbish, the economic stuff is multiple times worse.


De-carbonisation Outcomes

To quantify what might be achieved by any political action for de-carbonization by Western economies, the comparative tables below show the remaining effectiveness of each 100ppmv tranche up to 1000ppmv, with the total global warming in each of the five diminution assessments.

The next table shows the likely range of warming arising from these divergent (skeptical and IPCC) views), that would be averted with an increase of CO2 for the full increase from 400 ppmv  up to 1000 ppmv.

These calculations discount any feedbacks.  Feedbacks are used by alarmist climate modellers to exaggerate the amount of warming that might arise form increased man-made CO2 emissions.  However such temperature feedbacks are very questionable and may be either negative or positive.  But probably they are not massively positive as is assumed by CAGW alarmists.

psi 4

These results for countries and country groups show a range for whichever scenario of only a matter of a few thousandths to a few hundredths of a degree Centigrade.  However it is extremely unlikely that the developing world is going to succumb to non-development of their economies on the grounds of reducing CO2 emissions.

So it is very likely that the Developing world’s CO2 emissions will continue to escalate whatever is done by Developed nations.  These figures show that whatever the Developed world does in terms of decreasing CO2 emissions the outcome is likely to be absolutely immaterial.

A major stumbling block from the Kyoto Protocol on was the concern about unilateralism. It was the main reason the US Senate voted 95 – 0 to oppose ratification of Kyoto. It was the major reason fro the prolonged discussion at Paris and the final compromise of a non-binding agreement.

The table below is based on:

BP data on CO2 emissions by country


and the decollation of that data at


It assumes that the amount of CO2 released by each of the world’s nations or nation is reduced universally by some 20%: this is a radical reduction level but just about conceivable.

psi 5

It was known from the start and even acknowledged by people directly involved in the IPCC that even full implementation of Kyoto in its first draft would make no difference to atmospheric levels of CO2. In a Q and A Wigley said,

When you look at something like a Kyoto proposal, which is politically unacceptable to many people, how much difference would it make to the problem if it were enacted tomorrow?”

If everybody were to come on board with the Kyoto protocol, then that would slow down the rate of warming of global mean temperature, slow down the rate of climate change by a very, very small amount. So we have to clearly, in the future, do something a lot more dramatic than just the Kyoto Protocol. It’s a very small step along a pathway that is long and difficult.”


The extreme, economically destructive and immensely costly efforts by participating Western nations to reduce temperature by de-carbonization should be seen in context:

• the changing global temperature patterns, the current 18 year standstill and likely impending cooling.

• the rapidly growing CO2 emissions from the bulk of the world’s most populous nations as they continue their development.

• that Europe as a whole now only accounts for ~10% of world CO2 emissions and is likely to drop to ~7% by 2030.

• that the UK itself is now only about ~1.3% of world CO2 emissions and is likely to drop to ~0.9% by 2030.

• the minimal temperature reduction that might be achieved by de-carbonistion actions in the Developed world

• the diminishing impact of any extra CO2 emissions on any temperature increase.

• normal daily temperature variations at any a single location range from 10°C to 20°C.normal annual variations value can be as much as 40°C to 50°C.

As the margin of error for temperature measurements is about 1.0°C, the minuscule temperature effects shown here would only arise from the extreme economic efforts of those participating Developed nations attempting to control their CO2 emissions.

Thus the outcomes in terms of controlling temperature can only ever be marginal, immeasurable and thus irrelevant.


The committed Nations by their actions alone, whatever the costs they incurred to themselves, might only ever effect virtually undetectable reductions of World temperature. So it is clear that all the minor but extremely expensive attempts by the few convinced Western nations at the limitation of their own CO2 emissions will be inconsequential and futile.

Professor Judith Curry’s Congressional testimony 14/1/2014 [v]:

Motivated by the precautionary principle to avoid dangerous anthropogenic climate change, attempts to modify the climate through reducing CO2 emissions may turn out to be futile. The stagnation in greenhouse warming observed over the past 15+ years demonstrates that CO2 is not a control knob on climate variability on decadal time scales.”

Professor Richard Lindzen UK parliament committee testimony 28/1/2014 on IPCC AR5 [vi]:

Whatever the UK decides to do will have no impact on your climate, but will have a profound impact on your economy. (You are) Trying to solve a problem that may not be a problem by taking actions that you know will hurt your economy.” 

These quotes could be paraphrased as: 

doing nothing for fifty years is a much better option than any active political measures to control climate.”

As global temperatures have already been showing stagnation or cooling[vii] over the last eighteen years or more, the world should now fear the real and detrimental effects of global cooling, rather than being hysterical about limited, beneficial or now non-existent warming[viii].

My advice is the old Yorkshire saying, “When in Doubt do Nowt.”

Tim Ball