A sceptic investigates! Is there a causal link between global Co2 emissions and global temperature increase?

I have yet to be convinced of the link between emissions and temperature increase. The arguments made have been unconvincingly presented and seem to mostly rely on 'we are right' just agree. This is 'situation' is exacerbated by hyperbolic statements and headlines along, the antisocial antics and behaviour of end-of-the-world AGW idealists and a lack of cogent structured argument.

In a previous article (https://lnkd.in/ektUPucN) I analysed the IPCC projections from 1998 that catalysed spending on averting what was described as the climate crisis: Originally global warming, then climate change when the warming didn’t happen as projected. Then they changed the baseline so it looked like the planet was ‘warming up’ as planned and was close to the headline figure of 1.5 degrees Celsius, even though that headlined figure was based projections of reaching a global temperature above 1998 average temp, not the average temperature of 1850-1900! I invited people to trash the maths and tell me I was wrong but no-one came forward.

In january 2024 saw the headline of ‘hottest January ever’ that catalysed and explosion of headlines promoting saying that we were still advancing towards the climate catastrophe predicted (‘End of the world?’). So, I thought it was time to do a deeper investigation of the figures, purseu some logic and do some more maths, then write another article.

This is the result and to make it easier to understand I have produced some graphs. All figures, unless otherwise stated, are drawn from Copernicus data found here. https://tinyurl.com/57tcpvn3 The outcome was not what I expected but I have pursued the data, applied logic and the conclusions wrote themselves!

I am using the absolute figures (i.e. the measurements) not the figures after they have been 'adjusted.' What we find is that average global temperature for January is increasing. (No denying that!) however back in 2020 the temp for January was 13.02 degrees Celsius and in 2025 it was 13.23. So headlines of doom based on 0.21 degrees Celsius increase feels like hype to me.

Next lets look at the temperature for January each year against the average global temperature for each year. January temps are on the right hand scale, annual temps on the left hand.

We find the two pretty much track each other, but it can be seen that january temperatures have greater variation in highs and lows and so a January peak is not a reliable absolute and so not worthy of the hyped headlines presented in the UK. for examples

Scientists have warned that “dangerous climate breakdown” has arrived after the warmest January ever was recorded globally, defying expectations that 2025 might be cooler than previous years.

The average temperature last month stood at 13.23C, which is 0.79C above the 1991 to 2020 average for January and 1.75C above the pre-industrial level, according to European space agency Copernicus.

https://tinyurl.com/2e5s5was

For insight into modelling used by climate science: https://tinyurl.com/y4mk3s8b

What is interesting is this statement acknowledges that the average annual global temperature has increased by (only) 0.79C (as per my calculations in my previous article based on absolutes from 1998 to the present, as 1998 was the IPCC baseline year (as outlined above): https://lnkd.in/ektUPucN). According to the IPCC it was an increase of 1.5C based on 1998 we needed to worry about.

So, I hope you agree, that we have established that the hotest January ever headlines was hype, and one must ask why is this necessary if the science is already accepted and decided? However, the planet is heating up, albeit slower than the IPCC models predicted although it is only half way to the 1.5c level predicted to be reached by 2024-2030.

However, what stands out is the resilience of the trend line of increase. It seems to be tracking steadily upwards. This is not what we should expect given the amount of time effort and especially money that has been spent to stop this trend. So what is happening?

Firstly, the figures show that whatever is being done is not affectiing emissions made (outputs) nor is it absorbing those outputs (e.g. carbon capture/offsetting) as the component percentage of CO2 in the atmosphere is rising in line with emissions: or even bucking the trend- it seems to continue upwards despite a slight downward dip in emissions!

So, whatever is being done, it isn't affecting emission volume. In fact here is expenditure (as far back as I can find it) against emissions and where there should be a negative correlation (more money spent we should see a corresponding decline in emissions) there is a positive correlation. It also seems to correlate (but is it causation?) that when money invested reduces, emissions reduce- that is really weird.

So what about the link between Co2 and temperature. It is clear that the IPCC model doesn't work (outlined in https://lnkd.in/ektUPucN) as temperatures should be much higher based on Co2 volume increase. So is there are realtionship and if so what is it?

If we look at the whole period from 1940 there appears to be no correlation as the trend lines diverge. At the same time it seems something weird takes place in about 1980 where they cross.

Trend lines use past data to set the line and they can smooth out rather than highlight new ternds. To tease this out we need to look at the data in 2 parts- before 1981 and after 1981.

What we find is that around 1980 the temperature begins to track the co2 emissions, as shown by the trend line. I didn't expect to find this, but remember, I am just following the maths and the analysis. I find this pretty convincing that there is a relationship between increasing co2 emissions and temperature increase, which I assume must be due to reaching some 'tipping point' around 1980, where emissions began to link in a way they had not previously. Why has no-one explained this before, or why haven't I hear this? this seems pretty core to the argument for AGW?

Of course a driver of AGW emissions are human beings (by definition) and the other chart that correlates with emissions (and therefore temperature) is when population growth is plotted against it.

Note: Values as of 1 July of the indicated year. OurWorldinData.org/population-growth | CC BY

But there is also the question of what people are doing. When we look at growth in emissions by region we find the issue lies with Asia since emissions are falling or static elsewhere.

32.88% of all emissions comes from China : https://www.worldometers.info/co2-emissions/co2-emissions-by-country/ which has become a manufacturing giant to supply world demand.

And China dominates the 'clean energy technology manufacturing' https://tinyurl.com/3tkyeayp which may explain the correlation between spending on emission reduction and increase in emissions, since China is using 'dirty energy' to produce green tech. Information on who pollutes: https://www.worldometers.info/co2-emissions/co2-emissions-by-country/

So with a rapid sprint at he end we can summarise:

Summary

• There is correlation between co2 emissions and temperature.
• There may be causation but the IPCC model doesn't work: so the nature of the relationship is not proven.
• If it is one of causation, ie temp increase is caused by CO2 emissions then the data suggests that they increase with the increasing expenditure to address them. What is clear is that money spent on addressing emissions has not halted or reduced them.
• That whilst raw growth in population correlates to temperature/co2 increase is not the driver, it is human behaviour that causes emissions.
• There isa link to human behaviour taking place: manufacturing in China. Their industry has grown exponentially in totality and specifically to produce 'clean energy tech' whilst using dirty energy to do it.
• We can conclude that if the orignal statement that '1.5c increase above 1998 figures', was the level to be avoided, we are half way there. Good news is we have longer than predicted to solve the problem, the bad news is that so far nothing that has been done has changed the trend line.