An updatable series of short, printable, summary posts encapsulating the main points on particular critical issues short commentaries. 



The chart below gives an extremely revealing insight into how CO2 in the atmosphere has varied dramatically over time (a near 90% linear plunge in concentration the last billion years), and a stark lack of any consistent relationship with global temperature. Atmospheric CO2 levels are down over 2000 ppm in a largely one-way shift from the atmosphere to be locked up largely forever in marine limestones. 

The reason for the CO2 decline is the progressive, very largely one-way chemical reaction:

Ca2+   +   CO2  + H2O    -->    CaCO3(limestone)     +  2H+

This reaction effectively pulls CO2 from the atmosphere to dissolve in the ocean and react with abundant soluble calcium to form insoluble calcite (CaCO3), which is 44 weight percent CO2 by weight.  This reaction progressively moves to the right, eventually depleting the system in free CO2. In the chart above it has taken over one billion years to deplete the Earth’s atmosphere of over 2000 ppm, leaving only about 400 ppm remaining. The depletion rate for atmospheric CO2 seems to be about 4 ppm CO2/million years. At the present rate the remaining CO2 will be gone in 100 million years, at which time all life on Earth will cease because the lack of any available carbon.  This 100 million years does not seem to be an immediately threatening time line, except for the fact that plant life appears to function best at CO2 levels around 1000 ppm. The present levels of around 400 ppm (and includes the concerning man-made component  of 15 ppm) are well less than the ideal or optimum for plant life. This means that plants are presently starved of substantial, necessary CO2 in the present depleted atmosphere. The effect of this is vividly demonstrated in the illustration below.  Horticulturalists and others have long recognised that plants in glass houses with elevated CO2 levels perform significantly better than if under ambient CO2 conditions (around 385 ppm in the comparison below). This suggests that atmospheric CO2 is a significant fertilizer for plant growth, and doubling CO2 levels virtually double plant size and development. It appears that most plants appear to favour optimum atmospheric CO2 levels of around 1000 ppm. 

Looking more deeply into this it seems likely that this growth effect results from present atmospheric CO2 levels having been severely depleted in CO2 from the optimum levels for plants of around 1000 ppm since the beginning of the Cretaceous some 65 million years ago. Unless more CO2 is put back into the atmosphere, then this process is certain to continue with progressively declining plant yields. In order to get back to optimum plant CO2 levels of around 1000 ppm we would need to return to the atmosphere 600 ppm CO2. This would mean the equivalent of burning up to one half of all the world’s current coal reserves. We would not need to go back all the way to maximise optimal conditions but any increases in atmospheric CO2 would quickly show significant advances in agricultural production and global vegetation levels generally. Another benefit of higher CO2 is that plants need less water, as less water is lost through transpiration through larger leaf pores need to gather CO2 from depleted atmospheres. This means that plants are much more water tolerant, need less water, and are more adaptable to drier conditions. 

The above image is derived from:  Sherwood B Idso, President of the Centre for the study of carbon dioxide and global change.  Research Physicist with the U.S. Department of Agriculture's Agricultural Research Service at the U.S. Water Conservation Laboratory in Phoenix, Arizona, where he worked since June 1967. His science citation record: as of July 2000, Dr. Idso’s research papers had been cited in the scientific literature in excess of 6,500 times, more than an order of magnitude above the norm for all scientists of that time period.

The impact on agricultural and food production globally would be dramatic. CO2 at these increased atmospheric levels is not toxic, and has virtually no impact on global temperatures.

The best approach is to continue to burn fossil fuels (which can now be considered “clean coal” and “clean” liquid and gaseous organic fuels), with CO2 provided as a free by-product, to be transported and delivered free to every plant on earth by the wind and atmosphere. We would no longer need expensive and technically complicated, unreliable and intermittent energy supplies and toxic battery systems, but would have cheaper baseload power on call from existing well-understood, clean, coal and gas power plants which would be pumping much needed, cost free CO2 into the atmosphere to sustain and reinvigorate vegetation and agriculture.

CO2-based climate change is now seriously discredited, as are the failed climate scientists, and climate models that bear no semblance to reality.  The Earth may or may not be warming. If so it is not man-made and is returning to a long-term warmer normal that it has returned to after every previous glacial episode. We do not have to do anything, the Earth’s climate system is self-correcting and requires no heroic human input, or disastrous financial self-sacrifice, or expensive inefficient unproven green energy technologies.

There is however work to be done, to change emphasis, to slowly restore the CO2-depleted atmosphere and boost agricultural production through the development of now recognised non-polluting, clean, green, coal-fired base-load power stations.

Dr Robert Fagan
Geologist & Climate Critic 



The above chart displays the departures from mean global temperature over the last 4.6  billion years determined from geological climate markers over that period. The medial line for temperature represents the present-day temperature condition. Departures from this line reflect the magnitude of the change. For temperatures the maximum range above the medial line would be about 5-10 degrees. The dashed red line represents the long term, mean global temperature equilibrium position established over the last four billion years and lies 3-5 degrees above the present-day global average. The red dots above represent only seven times (associated with glacial events) in the last one billion years when the Earth’s climate has ever been at the IPCC arbitrarily chosen, preferred global present-day temperature setting. For most of Earth history conditions have been much warmer than at present, sometimes warmer & wetter, and sometimes warmer and drier. But for more than 95% of all-time conditions were 3-5 degrees warmer, and throughout most of that time there were no polar ice caps.

The several glacial periods represent minor disturbances in this long-term equilibrium temperature history of the Earth, due to any number of short episodes in sun activity, massive global volcanic episodes, periodic changes in Earth tilt, orbit and wobble (Milankovitch cycles), changes in continental drift configurations affecting ocean & atmospheric circulation patterns etc.

The steady-state climate model
It can be seen that for over the bulk of four billion years of Earth history, the global mean temperatures have been consistently warmer than at present and for the last 600 million years at least, some 3-5 degrees warmer than at present. This is remarkable temperature control to within 2-3 degrees over an enormous period of time. This is due to, and evidence of, the Sun and Earth maintaining a very powerful stable closed system that has achieved and maintained a powerful dynamic steady-state thermal equilibrium over that period.  A steady-state equilibrium system will always revert to the steady state condition if the equilibrium is disturbed (such as during a global glacial event), and will automatically, but slowly, work towards restoring the original long-term (in this case) warmer equilibrium conditions.

This model provides CO2 with a “get out of jail card”, it is proven to be innocent of being a dangerous exhaust gas and contributor to warming. Quite the converse, it is an essential atmosphere-delivered fertilizer and an absolutely fundamental component of coral reefs (44 weight percent CO2). Doubling atmospheric CO2 to a total of 800 ppm, would double agricultural production worldwide and double the number of coral reefs with no adverse effects. It also means that coal is now a lot “cleaner” as the major CO2 component of exhaust fumes is no longer toxic, but beneficial, and need not be separated and isolated at great expense. 

Global warming is no more than the Earth trying to re-establish temperatures to the very long-term equilibrium norm of being about 3-5 degrees warmer, a condition that during a long evolution, all life was optimally tuned to and adapted for. Nature has this well under control. Atmospheric CO2 has played absolutely no role in this and nothing man can do could materially make any difference. Re-equilibration with associated warming may take some time to re-establish itself, but it is not an existential threat to humanity. We cannot fight nature at this scale nor need we. This super-powerful, externally powered, Sun-Earth thermal equilibrium is successfully re-adjusting, automatically protecting our interests and we couldn’t be in safer hands. Man-made global warming plays absolutely no role in this process.

This is all very basic high-school science and chemistry. High school science classes teach 13 year olds to understand the origin, nature and power of equilibriums, and how equilibriums adjust to external pressures (Le Chatelier’s Principle). That most global climate scientists have failed to recognise or address this is concerning and perplexing. One can only presume that these scientists were somehow shockingly unaware of the near 4-billion-year temperature history establishing the existence of this very powerful dynamic thermal equilibrium controlling and regulating the Earth’s climate system.

In re-adjusting to the long-term equilibrium temperature conditions things may get warmer, sea levels may rise and the ice caps may completely melt, as things return to the long-term equilibrium conditions that for this system are normal. The parts of the Earth above 50 degrees latitude will flourish and bloom and at last meet their full agricultural and economic potential, but the lowest latitudes closer to the equator may be uncomfortably seasonally hot for some inhabitants, just as the high latitudes are impossibly cold for most now. Low lying island states and continental coastal fringes will be slowly drowned with sea level rises as polar ice inevitably melts. There will be some inevitable collateral damage, depending how far we are from that equilibrium condition, with some winners and losers, but overall the Earth will return to more optimum conditions for life as we know it, that were established over billions of years.

The Earth is not under any existential threat, but returning to normal. This has not been man-made.  Coal, CO2 emissions, renewable energy, the Paris Accord, inconvenient truths, current IPCC policies, and massive economic blood-letting are all irrelevant and have no effective role to play. Global warming is not triggered or controlled by anything on Earth, but by the overwhelming power of the Sun’s influence on Earth, and that is way beyond our control, but thankfully is controlled by powerful equilibria working in our favour.

To attempt to do anything on Earth such as an economically disastrous emissions mitigation policy would achieve absolutely nothing at horrendous cost globally and create a severe problem where none presently exists.

We cannot ignore 600 million years of the Earth’s most recent climate history showing the earth to be consistently a few degrees warmer than today and not regard it as being the climate norm and the future.

This model is so compelling and its implications so profound that it needs to be more widely circulated, promoted and discussed, particularly within the scientific community.   

Dr Robert Fagan. Climate Researcher                                           Web Page:  


An easily digestible explanation of the CO2 debate


For reasons and with evidence presented elsewhere, it is clear that the last one billion years of the Earth’s climate history and beyond absolutely establishes the fact that global warming is occurring, but is due to a natural re-equilibration to longer-term warmer conditions following a recent cooling event, all driven by the sun. This means that global warming cannot possibly be due to atmospheric CO2 or any other man-made influence.  Why pro-warming scientists and the IPCC have completely ignored this absolutely crucial evidence and its implications defies comprehension.

 Because of the present toxic attitude to CO2 it would be difficult for the general public and even most in the scientific community to believe any of the following claims.

CO2 is a hugely beneficial atmospheric gas that needs a complete rethink and further study. It offers considerable potential for a great many  unrecognized benefits for mankind in the future, particularly as a unique and extremely efficient fertilizer.  As a gas, CO2  is delivered automatically directly from the atmosphere  to plants worldwide.  If we doubled atmospheric CO2 to 800 ppm, we could effectively double agricultural production on land and in the oceans, worldwide virtually overnight.

CO2 is very stable, recyclable and as a fertilizer and an atmospheric gas, effectively delivers itself to where it is needed without any intervention from man.

CO2 is a colourless, odourless , tasteless, and non-toxic at levels up to a few thousand ppm.  Its benign character is reinforced by its abundant use and presence in all carbonated drinks and foods.

CO2  is a minor atmospheric gas  sourced most readily  from the burning of coal, its abundance  is largely self regulating in the environment and there is virtually an inexhaustible supply of it. CO2 as a commercial product can be delivered in gaseous, liquid or in solid form. 

As CO2 is not a contributor to global warming, and is not a noxious exhaust gas but is environmentally beneficial, we can cheaply burn organic fuels such as coal largely with impunity for energy and electrical generation purposes.  We no longer have to remove CO2 as a noxious exhaust gas, as it is in fact beneficial and not a problem waste product. We in effect already have "clean coal".

CO2 is a major and essential component of coral reefs (44 weight percent).  In fact if we doubled atmospheric CO2 levels to 800 ppm we could double the amount of coral reefs in existence.

The blackening of the name and reputation of CO2, and the almost universal ignorance science has of its important role and function as a beneficial atmospheric gas, almost beggar’s belief. The vast amount of energy and resources devoted to completely misunderstanding the role of CO2  and the wilful ignorance displayed  by those responsible is appalling.  It may be difficult to undo this damage.

The effect of increasing levels of atmospheric CO2 on plant growth.
The photo below shows a comparison of plant growth achieved in atmospheres of differing CO2 levels. This readily displays the fertilizer effect of increased levels of atmospheric CO2. The numbers below display the total CO2 concentrations.

The above image is derived from:  Sherwood B Idso, President of the Centre for the study of carbon dioxide and global change.  Research Physicist with the U.S. Department of Agriculture's Agricultural Research Service at the U.S. Water Conservation Laboratory in Phoenix, Arizona, where he worked since June 1967. His science citation record: as of July 2000, Dr. Idso’s research papers had been cited in the scientific literature in excess of 6,500 times, more than an order of magnitude above the norm for all scientists of that time period.

Corals reefs and CO2

Many of the low-lying island nations such as the Maldives, concerned about rising oceans may not realize it but it is the continued growth of coral limestone and its essential CO2 component that formed their island nation in the first place and is keeping their island nations above sea level now and has been for centuries. Coral like all limestone is are composed 44 weight percent from what was originally atmospheric CO2. Much of the worlds landscape is composed 44% of CO2..

Clean coal

If CO2 is not a polluting exhaust gas, but is in effect benefiting the environment, then we do not have to remove it from coal exhaust fumes in expensive carbon capture and storage  technology, and therefore we already have to a large extent “clean coal”.

Nor should we abandon coal mining, which contributes some $60 billion to the Australian economy every year.  This $60 billion is responsible for keeping well over one million Australians in employment and out of poverty every year and has done so for the last 30 years at least. These one million people are not just a few thousand directly involved in coal mining, but are scattered throughout the entire economy where that $60 billion gets spent. The export of coal to places like India and China has the potential to lift tens of millions of other people out of poverty world-wide. Coal is an incredible gift, contributing to global prosperity, and is not contributing to global warming. 

For more detailed explanation and analysis access the dedicated web site:  .

Dr Robert Fagan 
Climate Critic.  




This article relates to the climate change debate and the problems that will arise when the existing favoured climate  models are found to be totally baseless and the product of poor science and even poorer scientists, who captured the debate, completely misunderstood the nature and cause of the problem, and proceeded to formulate  a totally disastrous and ineffective response. This will inevitably seriously damage the reputation of science and public confidence in scientific pronouncements.  

A scenario is playing out today where serious scientific investigation and analysis have been abandoned, and replaced with a woefully inadequate understanding of the basic science involved, led by the worlds supposedly most senior scientific organisations.  The complete misunderstanding of the basic science involved is incomprehensible.  The existing man-made atmospheric CO2 argument for the cause of atmospheric global warming can be completely destroyed in just one graphical illustration (below), showing the temperature and atmospheric CO2 levels for all of geological time on Earth (4.6 billion years), right up to the present. 

If you can understand this simple chart of climate data over time, then you can understand why climate warming is occurring, why atmospheric CO2 is not involved, and why warming does not pose any existential threat.

Even a cursory examination of the mean global temperatures and atmospheric CO2 levels over geological time displayed in the above chart, shows no consistency between the two, completely destroying any evidence of a causal link between atmospheric CO2 and temperatures. This chart also clearly indicates that mean global temperatures have been held at a remarkably stable 2-3 degrees warmer than presently experienced, for almost all of geological time, up to the very recent Pleistocene Ice Age. Present day mean global temperature levels (for some reason favoured by climate scientists) have only ever existed for exceedingly short periods when the Earth is entering or emerging from very rare, short-lived glaciation events in the past (see black dots along the present global average temperature reference line). From this data it can be seen that global warming is the earth trying to re-establish the longer-term, warmer, normal temperatures that existed for nearly all of geological time. The earth’s climate is just reverting to a slightly warmer, normal condition, after a short sharp cold event. The very stable, sun-controlled, dynamic, thermal equilibrium, that has existed controlling Earth’s temperature for billions of years is gradually being re-established. There is no existential threat. Things are returning to a warmer normal condition that initiated, sustained and supported all life on Earth and evolutionary processes for more than four billion years.  We could not be in safer hands and do not have to do anything to achieve long-term climate normalcy.


The only reason that the man-made CO2 model ever achieved prominence is that climate scientists could not come up with another explanation or mechanism for observed warming. Unbelievably it seems that virtually no one looked at four billion years of climate and atmospheric CO2 history, even though the data and charts have been around for over 30 years. 

 Warming will occur, glacial ice will melt, some sea-level rises are inevitable, and small islands and low-lying coastal regions will be inundated. The ice sheets in the polar regions are likely to recede and completely melt (polar ice has existed for only 20% of Earth history). The big winners will be all latitudes above 40 degrees with incredibly increased and productive growing seasons right up to the poles. This includes all latitudes above the Canadian border and the Alps in Europe, in the northern hemisphere. Less important in the southern hemisphere landmasses. The low latitude equatorial regions will be warmer but manageable. Remember that very few people can exist in present polar regions without considerable technical assistance and a somewhat warmer equatorial existence is far more liveable than a polar one. 

The dismissal and total abandonment of present global warming models is inevitable once the reality of the situation is more widely recognised and accepted. This will cause an immense backlash against science (particularly climate scientists) for completely failing to understand the problem. The global climate alarmists either completely ignored or did not even realise that an examination and understanding of past climate experience would reveal the nature of the problem and the solution. How could they miss this? It shows remarkable ignorance and very poor science, by many thousands of very poor scientists (including very poor leading scientists) and their fellow travellers. Also, why did other scientists, opposing the CO2 model, not seem to realise this either and alert the world This suggests that they too need to shoulder some of the blame.  Exceptionally poor-quality science and the poor quality of scientific leadership have a lot to answer for and the greater public will be demanding an accounting, particularly the multitude of seriously misled and disillusioned followers who put their seriously misplaced faith in science.  Bad science and the manipulation of public opinion by scientists, leftist and green politicians, public commentators, the media, and a range of vested interest groups, and those wishing to further their own agendas world-wide was allowed to run wild and unchecked, made worse by those supporting unsound science endeavoring to stifle, censor or completely shut down the debate. 


The massively deluded public picked up the debate and ran with it demanding extreme policy action and economic and social sacrifice in arguments bordering on the hysterical. This extended into a rush into heavily subsidized renewable energy policies, proposals to outlaw fossil fuel mining, even extending into faulty coral reef science and the pledging of enormous amounts of public monies in supporting failed theories and failed scientific expertise in this and in many other areas.  


Those who did recognize the problem could not break through the perimeter fences of the scientific establishment, politicians and the media to get their message across. The view that “the science is settled”, and “97% scientific consensus’’, although patently false, prevailed. Anyone who believes either statement has any validity does not fully understand the nature of science. These are political pronouncements, not scientific ones. Contrary views including a less than well-accepted petition of 31,000 concerned American scientists, expressing opposition to the view that CO2 is contributing to catastrophic heating of the Earth’s atmosphere and climate, and that instead that there is substantial scientific evidence of the beneficial effects of atmospheric CO2, has been circulated: Web link:

Hopefully we will be saved from the implementation of totally ineffective, catastrophic man-made economic and social policy disasters that are in the pipeline. These tend to be designed to mitigate totally innocent atmospheric CO2, ban coal mining and the burning of fossil fuels, seriously curtail agriculture and transportation policies, promote expensive and less effective energy technology, and provide vast sums to supposedly climate-affected poor nations, and for fatally flawed research into failed climate and coral reef research programs. 


Warming will create some problems and mitigation of those will be necessary especially where climate zones shift pole-ward, some colder zones are eliminated (ice bound polar regions), and new warmer equatorial zones are created. Rising ocean levels and some changes in climate patterns need to be thought through and managed. Measurable warming rates following recent warming episodes recorded in recent polar ice cores can be used to determine rates of change. There will be winners and losers. But mainly there will be enormous winners. 

For more detail please refer to the two brief explanatory articles presented in Posts One and Two above:
What is causing global warming”, and “An easily digestible explanation of the CO2 debate”. 

Dr Robert Fagan,
Geologist & Climate Critic





The Greenland Ice Core Chart for the last 10,000 years, presented below, displays the cyclic and regular  character of at least 10 warming events up to the present time, from which the Earth completely recovered. The present warming event seem to be the next in line in this series. Apart from increasing as ocean temperature increased, CO2 does not seem to have played any role in the process. The warming process seems natural, regular, short-livid and harmless. 

Ice core data is used because it gives a continuous time record of samples that can give temperature and atmospheric CO2 concentrations. Ice core data from both polar regions and alpine glaciers can be used to extrapolate climate data for other latitudes. 


The CO2 climate driver theory suggests as the CO2 occurs first, there should follow a red line (temperature increase) matching the 415  ppm CO2 increase along the right axis of this chart. The 8-10 degrees F missing from this chart will never appear as the CO2 occurs first in this instance (unlike for all the earlier portions of the chart), & is not a climate driver. In the other portions of the chart, the temperature occurs first and is a CO2 driver. 

A very unusual relationship between the north and south polar icecaps ice core data is revealed in the chart below, with many peaks being reversed between the two poles. 



Some misunderstanding exits on how global warming occurs and how it causes sea-level increases. Recent warming over the last 10,000 years has been cyclical (a warming pulse, followed by a cooling pulse). Sea levels rise in the warming cycle due to increased land-ice melting and warm water volume increases. Sea levels lower on subsequent cooling as land-water freezing occurs and cool water volume decreases. Some 10 cycles are recorded in the most recent 10,000-year chart below. 

Sea levels rise slowly over the warming 100 years by about 1-2 metres, then slowly lower again during the following 100-year cooling cycle. The two halves of this cycle roughly cancel each other out with no net sea level rise overall. This has happened about a dozen times in the last 10, 000 years, with little overall change in net sea-level. 

 The very significant, very large sea level changes in the past (the Pleistocene Glaciation) have been caused by single major cooling/warming events of several degrees, where the temperature has change (down followed by up) by 8 degrees or more. The most recent Pleistocene event of this magnitude starting about 15,000 years ago. 
The chart below shows sea level changes over the last 20,000 years, including the major heating event beginning about 18,000 years ago resulting in a sea level rise of about 120 metres, corresponding to a temperature increase of about 8 degrees (from -8o to 0o). Since about 7,000 years ago sea level changes have been minimal (up and down by 1-2 metres), even though there have been several, warming/freezing pulse/fluctuations during that time, representing temperature fluctuations of 1-1.5 degrees). These sea level changes tended to cancel each other out and should continue to do so in future, if as seems likely, similar temperature pulses, such as we are currently experiencing, continue to occur.  There seems little concern for serious sea level fluctuations beyond needing some remedial local engineering work. 



 The Greenland & Antarctic Ice Core Data 

Ice core data recorded from a number of ice locations, allows very close sampling and a continuous detailed climate record not achievable by other methods, but only extends back some 800,000 years and immediately relatable to cold, high latitude environments. Some global climate extrapolation is possible.

In the chart below over 350,000 years of both temperature and atmospheric CO2, recorded from Vostok ice core data are presented. A strongly developed, very regular, asymmetric, zig-zag sawtooth pattern is revealed, and a close correlation is noted with temperature narrowly preceding CO2. What is unusual is that there has been no temperature increase to match the 200 to 415 ppm increase in CO2 recorded in 2019. The magnitude of missing temperature should be some 8 degrees F, measured and scaled against other peaks in the chart. Is this because this is a known instance where CO2 increased first, before temperature, and provides proof that CO2 is not a temperature driver?  Or is there a temperature delay, not yet registered,  where temperature follows CO2. In this latter case this temperature delay is certainly not seen elsewhere in this chart? 

Milankovitch Cycles 

The repeating 100,000 year, asymmetric zig-zag pattern temperature and CO2 pattern displayed above, and the other smaller repeating peak and troughs cycles, seem to conform to cyclical patterns observed for the Earths orbit around the sun (eccentricity), and systematic Earth axial tilt, and wobble behaviour (called precession), recognised as Milankovitch Cycles. The geometry, character and periodicity of these is displayed below.

What is causing these climate cycles?

The temperature relationship to the Milankovitch cycles (particularly the100,000 year orbital eccentricity cycle), is clear. Each eccentric cycle begins with short rapid warming during the short ellipse phase with the Earth closer to the sun, followed by the much slower cooling phase as the ellipse extend to it's maximum.  There is some debate as to whether the shorter warmer orbit is sufficient to account for the heating, or if the associated increase in greenhouse CO2 provides additional slightly lagging feed back. Orbital cycles certainly control the temperature cycles but cannot by themselves account for regular CO2 cycles. The smaller Milankovitch cycles contribute to the lesser peaks. 

The regularity of the 1000 year cyclical peaks the regular smaller peaks between, registered and illustrated in the GISP2 Greenland Holocene ice cores featured below, are also likely to have as yet unrecognised celestial controls at these much smaller time scales. 




The existence of differing CO2 scales on differing climate charts recorded in the literature is largely a reflection of the uncertainty in measuring past atmospheric CO2 levels. These are normally determined by using various proxies for estimating atmospheric CO2 at the time and the varying degrees of uncertainty or error in achieving that measurement or approximation. 

 The first chart below illustrates the range of proxy values over the last 500 Ma.  The range of uncertainty is revealed in the error bars & highlighted in the yellow shading which increases in uncertainty as you go back further in time.  


The second chart illustrates the range of proxy values over the last 60 Ma & the range of uncertainty revealed in the error bars. The blue shading again shows how the range of uncertainty increases as you go back in time.  The accuracy of the CO2 readings is likely to be much higher as we approach the present, and much more uncertain particularly during the Cambrian to Carboniferous. 

The third chart below is a useful chart that asigns more generally accepted higher CO2 levels in earlier times and is a useful diagram summarizing a lot of important information across 600 Ma . Note in most of these diagrams the time scale is variable (approaching being somewhat logarithmic) as it is too long to be shown meaningfully at a singe scale. This distortion also makes representation across time somewhat confusing for those nfamiliar with the concept of variable time scales.. 

Below is a useful diagram sumarizing a lot of important information across 600 Ma. The Time and CO2 scales will tend to vary in these diagrams in keeping with the preference  of the author. 

There has been an almost continual decline in atmospheric CO2 over time because there is a very important equilibrium reaction between atmospheric CO2 and the CO2 that dissolves in the ocean to form bicarbonate (HCO3-), and for that bicarbonate to react with dissolved Ca2+ ions to form limestone. Atmosphereic CO2 is being continually depleted by this reactin and process. Limestone is 44% CO2 by weight, and that is where most of the CO2 progressively lost from the atmosphere has ended up. The last graph below covering the last 140 million years, shows that the CO2 decrease is roughly 35 ppm per million years  and in less than 10 my nearly all atmospheric CO2 would be entirely depleted and all life on Earth would cease.  That atmospheric CO2 is rising now, is only because since the industrial revolution, man-made CO2 entering the atmosphere for the first time is exceeding the natural progressive loss into the oceans. This is only possible because we have reached such catastrophically low levels of CO2 in the atmosphere.