Is it a Greenhouse Gas?
Does more of it warm the world or not?
How big might the CO2 problem be?

There is a structure to these papers, which should take us through some very logical organised steps to remove a number of obstacles to the clear thinking required for such a complex subject. This will allow us to concentrate on the subject and the facts and hopefully reach some conclusions.

The water has been very muddied by those wishing the Climate isn’t changing, or that if it is – it isn’t our fault. Perhaps we can clear that mud. So:

In Part 1 we examined the impact of a warming climate. This showed our situation would be dire if the temperature increased by more than a couple of degrees, but difficult even at one degree. (I also explained my methodology for the work and showed why we should not base our understanding of climate on the climate models).

In Part 2 we showed that man has been altering the climate for at least 11,000 years and that using short periods from climate history across this period to prove or disprove climate change is not credible. Those who depend on such periods simply don’t understand the subject, and their arguments and conclusions need to be ignored or at least strongly contested.

We have perhaps already moved our thinking forward significantly because Parts 1 & 2 have perhaps brought new information and facts to bear, and partly because I cannot think of any sceptic’s argument that doesn’t take relatively microscopic periods of recent climate history on which to base their case. In a later Paper, after we have a much wider understanding of the subject, we will examine many of those arguments to see if they do hold up – or not. We only want the truth. This leaves one primary significant initial gap in our knowledge fundamental to this ‘debate’, which we need to get under our belt early on and is much argued by the sceptics:

Is Carbon Dioxide a Greenhouse gas, and if it is, does more of it mean the climate warms – or not?

Parts of the text I consider particularly important, often summaries, are in soft red; we will sometimes be dealing with ‘facts’ which by definition are unarguable and shown in dark green, but one purpose of the work is to present my hypotheses which will be shown in blue.

The Greenhouse Gas (GHG) issue is fundamental to this science in the full sense of that word, but of course there are lots of these gases – not just Carbon Dioxide (CO2). And to show how complex it all is, water vapour is also a GHG as well as a solar reflector! There are a few primary questions about CO2 that constantly repeat, certainly in the media, but nobody ever seems to answer them satisfactorily so we will deal with them here. They need to be ‘put to bed’ so we can move forwards:

  • Does increasing atmospheric CO2 ‘force’ the temperature of our Planet up or not?
  • Are we in a natural climate cycle or not, so is the level of CO2 in our atmosphere increasing to above where it has been before?
  • Is the increasing CO2 in our atmosphere the result of human activity (anthropogenic) or not?

Much of a meal is made of these questions, and goodness knows how many words have been written and film hours made on them, but the answers are simple and we may find – certain. I will use far fewer words here to address these questions! If increasing carbon would make no difference to temperature then the other questions don’t matter, so we will address this first.

Does increasing atmospheric CO2 ‘force’ the temperature of our Planet up or not?

It seems odd to have ever had a debate on this question, presumably explained by the lack of scientific knowledge of those taking part and the reluctance of the scientists to join in.

reflective earth image

In Part 2 we explored the albedo (reflectivity) of the planet’s surface because part of the arriving solar radiation (sunshine) is reflected back out into space while the rest stays here to warm us up, and because we have been changing it. We saw that the temperature of our planet is a function of the balance of the heat arriving and departing, and that the departing heat is the sum of reflected solar radiation AND radiated heat – our planet is a warm body in space so emits heat like a radiator. All that is precisely correct but now we have to add the Greenhouse Effect, discovered by Joseph Fourier in 1824 and proved by John Tyndall in 1859 – NOT NEW science.

Given Carbon Dioxide is the focal GH Gas, let’s just see what it does in the atmosphere.

The carbon dioxide molecule is transparent to short wave radiation (sunshine) which passes straight through but absorbs long wave radiation (radiated heat). When radiated heat collides with a CO2 molecule in the atmosphere – it is absorbed, but as the molecule cannot keep gaining energy it is released again. It was going out into space, but when it leaves the molecule it can be going in any direction – so every time radiation hits one of these molecules some that would have gone into space comes back again – and warms us up. The ‘Greenhouse’.

We might think the Greenhouse Effect is all bad news, but not so. It is what makes life here possible for most of life on Earth, as without it the average surface temperature would be about -18°C rather than the +15° it actually is. So thank heavens for Green House gases. But if we increase the amount of CO2 in the atmosphere we increase the probability that outgoing radiation will hit CO2 molecules and that increases the amount of radiation returning to the planet – to the surface and into the atmosphere.

It really isn’t very difficult to understand that:

  • If you double the amount of CO2 in the atmosphere
  • you double the number of CO2 molecules available to be collided with
  • you double the probability outgoing radiation will collide with them
  • you double the amount of radiated heat interrupted from leaving Earth
  • which doubles the heating effect of the Greenhouse caused by the CO2.

So the relationship between the amount of Carbon Dioxide in the atmosphere and the greenhouse warming effect of it – is (almost) linear. This doesn’t mean the temperature on Earth doubles – it just means the warming effect resulting from the CO2 is doubled.

[Now before I am scientifically criticised, it isn’t exactly doubled though you wouldn’t measure the difference from that. This is because as the atmospheric CO2 content increases, there is a higher probability that one CO2 molecule will be exactly behind another one – and the second is then ineffective. So for the purists, the relationship is not quite linear, though for the concentrations we have and are worried about it we can take it to be linear].

There is a lot going on in our atmosphere keeping Earth at about the temperature we are at, have been at and will be at – but it is a simple fact that if the Greenhouse gas concentrations increase, then the temperature of Earth WILL increase proportionately for the gas concerned unless other factors change.

But these might worsen the problem as well as improve it. Both are scientifically possible.

It is therefore bizarre that the sceptics have been allowed to argue that increasing GH Gases have no effect on temperature, while some have even argued the temperature goes down when gas levels go up! But now we know from Papers 1 & 2 there are lots of other factors affecting temperature on either a short or long term basis, so if something else is causing temperature to drop while greenhouse gas concentrations increase, and if the driver to decrease temperature is greater than the GHS driver to increase it – temperature may drop exactly as the GHG levels increase. This is totally compatible with the warming effect from increasing Carbon Dioxide concentrations.

There is another fact to consider, that the climate never did react in decades or even in hundreds of years to any temperature forcing and you have the evidence in the charts I have included in this series. And another is that we have a vast amount of ice on the planet mostly at very low temperatures of – 40° to – 50°. Just melting ice uses huge amounts of heat energy which comes from the atmosphere and oceans, so there will always be a lag between a forcing of the temperature and the temperature itself rising to a stable level.

Is the level of CO2in our atmosphere increasing to above where it has been before?

And if so – Is it significantly above?

I would love £1 for every time I have been asked or told “The climate always has cycled so there is nothing unusual with where we are at. There isn’t a problem – it is all made up”. The climate does cycle as we have already shown, so the prime question is “are we within the normal limits of the climate cycles – or not?”

We are in a privileged position having the original data for the last 470,000 years and the plots for the last 650,000 and 800,000 years. We can therefore really answer this question for the last almost 1m years at least.

During that period there have been many climate cycles, 6 in the last 650,000 years as you can see below, but we don»t have to concern ourselves with even earlier cycles as we are only worried about where our climate is going in the short and medium term, and the last million years will certainly define that. Anyway, there is a reason the climate cycles over 600,000 years ago were different from those over the more recent period (we will find there is always a reason), so let’s take a look at the last 650,000 years, but before doing so many of us find numbers with so many zeros on the end impossible to comprehend. Here therefore is the data plotted, showing the carbon record over the last 650,000 years with the timeline of human development on it so we can make the connection between the two. We can therefore get human development into perspective from the most recent climate cycle.

The CO2 plot over the last 650,000 years

Carbon Dioxide plot over the last 650,000 years

Note: on this plot the left end shows where we were in 1800 whereas on most temperature/carbon charts the most recent time it is on the right.

Interesting I think, not just for the record of CO2, as it also shows how briefly modern man’s footprint has been on this planet and how our development and spread across it are actually functions of the climate cycle. It is considered that modern man evolved in Africa about 160,000 years ago which was during a deep ice age as you can see on the chart, and referring to Part 1 of this series we can see that the area we evolved in was ‘habitable’ at that time whereas Europe would not have been. But in a deep ice age so much water has been turned into ice that the sea level was about 125m lower. At this time Africa was connected to the lands to the north and north east.

But 136,000 years ago the world’s climate started warming, so as the world warmed – the ice melted – and sea level rose – cutting Africa off from the land near it. In fact as that warm period was a bit warmer than this one (see Part 2), sea level rose to about 25m above where it is now, just as a result of being about 2° warmer than in 1800. Man’s early development was therefore confined to Africa.

Then around 100,000 years ago with the planet sinking back into another ice age and with sea levels dropping, we escaped Africa (as it again became attached to the Arabian Peninsula) by crossing into what is now Yemen and through the Middle East. We continued inhabiting the world excluding the northern area covered by ice or ice tundra while the planet warmed, and finally inhabited northern Europe from about 8,000 years ago when the ice age was retreating and northern Europe warming up.

Referring again to Part 2 in this series we saw the spread of agriculture to Northern Europe about 6,500 years ago. It all fits together as I hope this series of Papers will, and having a good knowledge of these various timelines will be extremely helpful working through climate. As we are beginning to see, if we put all the various sciences together with all their research data, the puzzle goes together. But we can also see we are not working with short time scales.

There is another element of particular interest on this plot and a reminder of the enormous impact climate changes can have on our species. 74,000 years ago (shown by the asterisk) Mount Toba in Indonesia, a super volcano, erupted or rather exploded. This created a major change in the climate which we call a ‘nuclear winter’ and which lasted for 6 to 10 years, robbing the land of the ability to produce much food reducing the human population to around 10,000 adults. We have already seen that any change in our climate will have an impact on our food supply (and that for all other life forms on Earth) and this gives some idea of the impact of a significant change even when short term (a few consecutive years). With a 7 billion and still growing population, of who around 2 billion normally go to bed hungry, any change would be likely to prove very critical.

So during this entire 650,000 years – 5 times longer than since modern man evolved; 60 times longer than agriculture has been practised and 2,600 times longer than since the industrial revolution – the level of CO2 in the atmosphere has not exceeded 300ppm. And during that period in didn’t ever drop below 180ppm. It has been in this range for a very long time.

Now we run into a difficulty with the presentation as it may already be obvious that on this scale the recent increase in carbon is a vertical line which doesn’t convey the whole story. So let’s first show what is happening on this scale:

Carbon Dioxide over 650,000 years to present

Note: this plot is properly scaled and doesn’t misrepresent the facts in any way at all. THIS is real. THIS is what is happening and will continue to happen if we don’t dramatically change the way humanity lives.

If you watched Al Gore’s film ‘An Inconvenient Truth’ you may recall seeing just the blue part of this chart (ending below where I have marked 2012) with Mr Gore going up in a fork lift truck to demonstrate how relatively high we have already pushed atmospheric carbon, and as you can see, he wasn’t kidding. But here I have also shown where it is going if we carry on as we are till 2025, but considerably reduce our carbon emissions after that. This is shown by the red vertical plot on the right starting above the end of the blue plot. He would need a helicopter or hot air balloon to reach the top of this plot!

  1. 1992 is marked as it was the year of the first Earth Summit in Rio when the figure was 356ppm. This was the first time ‘the world’ had met to seriously consider our environment and from which came the Kyoto protocol – designed to control global CO2 emissions. It started the IPCC with all their periodic reports but was also the time that the US government decided to both ignore the problem and really stop the rest of the world reacting.
  2. The next date is now, Feb 2012. Atmospheric CO2 is at 392.74ppm so within just 20 years since Rio it has risen by 37ppm – or 30% of the natural range of 180ppm in just that 20 years. This is an astonishing increase in such a short period of time given we also know the climate doesn’t and cannot react fully in these short time frames. It also quite dramatically shows what the Kyoto protocol didn’t achieve.
  3. I am aware that many working in climate science consider passing through 450ppm to at least be critical, so that point is shown, and with emissions as they currently are we will pass through this between 2035 and 2040. In this context ‘Critical’ means we would have lost control of climate after which we would be spectators in a heating world. But some believe the ‘critical’ point is much lower than 450ppm. It is looking between hairy and scary.
  4. The now infamous IPCC reports present the future levels of carbon under a considerable number of scenarios ranging from ‘we react instantly and substantially’ to ‘we carry on as we are’, but their most optimistic figure for the year 2100 is about 550ppm so that point is also shown.

Given we know the temperature range of the recent cycles has ‘only’ been about 11.5° for that 120ppm range, and given we know from Part 1 of this series that every single degree rise is going to impact on us significantly, shouldn’t we be seriously concerned that we have already increased the range to 213ppm, and at current rates of emissions we will have doubled it to 240ppm within about 25 years.

How fast is it rising compared with pre-human historic figures?

Comparison of historic and current changes in atmospheric carbon.

The levels to which we have pushed and are pushing the CO2 content of the atmosphere are of course the critical factor, but IF it is a problem, the lower the maximum level we reach would at least reduce the size of the problem. The rate at which we are increasing the figure is extremely important so let’s now look at the figures and some comparisons:

  • The time taken to move the planet from a deep ice age to the top of a warm period was around 11,000 years, so during that period the natural climate cycle increased atmospheric carbon (from 180 to 300ppm) by around 0.011ppm/year.
  • This conceals the greatest rates of rise over shorter periods during these historic rises from ice ages, which were around 0.02ppm/yr (this figure from the climb about 241,750 years ago).
  • Now lets’ compare that with the current annual increase which we can again obtain from Mauna Lao in Hawaii, and here it is shown over the last 50 years.

Comparison of recent annual rates of change in atmospheric CO2 levels

chart of growth rate of carbon dioxide at Mauna Loa

The figures have been averaged across each decade shown as the horizontal lines , so we can see very clearly just how fast the rate of increase has itself been increasing from 0.85ppm during the 1960’s to 1.97ppm during the most recent decade.

All those numbers above are quite difficult to get a handle on unless you constantly work with numbers, so to visually compare the rate at which atmospheric carbon has moved in the last million years with what is going on now, the bar chart below represents it to scale.

Comparison of current increases in atmospheric carbon compared with the last 1m years

Carbon dioxide bar chart
The left vertical axis shows the annual increase in CO2 in parts per million and the bars are as follows:

A to D are Pre Man

  • A. The maximum pre human annual decrease in carbon that I can find 307,000 years ago was 0.029ppm/yr.
  • B. The average pre human decrease between a warm period and the bottom of the next glacial was 0.00017ppm/yr. It is on the chart but is less than the width of the felt pen.
  • C. The average rate of increase from a glacial to a warm peak was 0.0.011ppm/yr.
  • D. The maximum rate of pre-human increase 241,750 years ago was 0.02ppm/yr.

E to G are Post Man

  • E. The average increase in the 1960’s was 0.85ppm/yr.
  • F. The average increase in the first decade of this millennium was 1.97ppm/yr.
  • G. The projected annual increase by 2025 if we carry on as we are would be 2.50ppm/yr.

Yet again I have to make the point that the above chart is precisely to scale, so the incredible difference between what the planet left to herself does and what we have done is difficult to describe. Given we have shown that CO2 is a greenhouse gas and more of it necessarily forces the temperature upward, I for one decided long ago this was a matter needing great attention and that we simply have to understand what impact this will have in the medium to long term. Generations come and go in roughly 25 year periods, so those being born now may have something extremely big to deal with. They may not, but the scale of the potential problem requires us to take a serious look at what will, or might, happen.

Is the increasing CO2 in our atmosphere the result of human activity (anthropogenic) or not?

Luckily we don’t have to go into lots of proof here as it is clearly impossible for the rate of atmospheric carbon increase to go from the extremely low pre-human levels on the last bar chart to the massive figures we also see there without there being an un-natural reason. After all, the historic figures represent a million years of history. Add to that the fact the increase in CO2 coincides exactly with man’s industrialisation; that we know about how much fossil fuel we burn each year and the CO2 impact of that, and that this explains the atmospheric increase while nothing else going on naturally even starts to explain it – so with certainty we know we are the cause. If you wish to doubt that, and I hope nobody does, then with the evidence we have you would need to explain where the increase comes from with great precision, and you should get a Nobel Peace Prize if you can.

Wishing or hoping we are not the cause is not evidence.


We have worked through how CO2 functions in our atmosphere; shown it is a greenhouse gas; that more of it up there does increase the warming effect, and that considering just the gas – the impact on the warming is linear, so doubling it doubles the gas’s warming effect.

An instant observation for many is that the temperature has not reacted following the huge rise in carbon and this is the primary reason people assume there is no relationship between carbon and temperature. I have noted that there are two reasons why that is not incompatible with a warming climate:

  • We are simultaneously doing all sorts of other things that are affecting climate, some of which are forcing the temperature down – notably increasing the reflectivity of the planet’s surface as we saw in Part 2 and by putting huge amounts of rubbish into the atmosphere. This adds to ‘The Parasol’ which reflects arriving solar radiation back out into space, cooling the planet.
  • In order to melt ice a huge amount of heat energy is required (the latent heat of ice to water), so any net reduction in ice volume – whether floating or on land – reduces the temperature of our atmosphere OR stops it increasing as much as it otherwise would.
    To get a quick handle on the scale of this factor, warming 1 litre of water by just 1° uses 4 units of energy (K.joules) while starting with ice at 0° and finishing with water at 0° uses 334 of those units. Just melting one ice cube uses the same energy as heating the melted water from that cube through 334°. Now consider the impact of a 1,000,000,000 ton iceberg going from – 40° to 20° water! You will probably think “A 1 billion ton iceberg – where does he get that from?” Well, right now we are waiting for one to break off the Pine Island glacier in Antarctica at least 150 times that big!
    Interestingly I have never found a sceptic discussing this.

I have shown that the actual increase in the forcing of the temperature is the net effect of the factors pushing it up and those pushing it down, so if over a short period those pushing it down are bigger than those pushing it up, the forcing is negative. Short term temperature changes cannot therefore be used to argue anything unless every factor affecting temperature is both known and quantified and I am not aware of anyone anywhere who can do that.

We have then seen that the level of CO2 in the atmosphere is completely beyond anywhere it has been through history, and so far above where it has been that if we make any connection at all between the gas and the global temperature, it would be bizarre to ignore the issue. But we have also seen that it is now growing at ever increasing rates, and that left to nature to bring down again, it would take forever to get back within the pre-human range. Putting figures on that, to take it from where it is today in February 2012at 392.7 4ppm to 300ppm (at the pre-human rate of decline) would take 545,530 years. This is 5 complete pre-human climate cycles; 3.4 times since the start of modern man in Africa, or 50 times as long as the time between now and when man invented agriculture.

It is in fact difficult to find words to describe humankind’s continuing refusal to do more than ‘research’ the subject as the implications of getting this wrong are beyond words.

And finally I have argued that the increase can only be the result of human activities.

In these first 3 papers we have therefore seen that:

  1. The historic temperature range between ice ages and warm periods has been about 11.5°.
    We have also seen that the climate we have is about the best possible for human inhabitation of the planet, so even a 1° rise would be significant, and rises of over 2° or 3° would be likely to have a huge impact on our species and civilisation.
  2. We have shown than man has been altering the climate, not since the start of the industrial revolution, but over the last about 11,000 years since we started agriculture. The notion therefore that the climate is just too big to alter by man’s activities is incorrect.
  3. We have also now shown that CO2 is a greenhouse gas; that we are responsible for the meteoric rise of it in the atmosphere; that it has increased and is increasing the temperature forcing due to the greenhouse effect, and that left to itself the planet would take an eternity to return to pre-human intervention levels.

I suspect this may be sufficient to focus the minds of those who read this on trying to understand this subject better as with just these three elements, most of the sceptics arguments are taken apart.