Central England Temperature (part 6)
A sideways look at the longest instrumental record of temperature in the world
In part 5 of this series I continued my support of alarmism by considering three mathematical models that linked mean annual Central England temperature observations (HADCET) for the period 1659 – 2021 to values for atmospheric CO2 concentration for the northern hemisphere. We discovered that all three models (linear, nonlinear, loglinear) gave near identical results over the range of observation (275 – 420ppm CO2) but differed markedly in their predictions for future scenarios of 1,000ppm and 4,000ppm CO2. Only one model (loglinear) got close to estimating the theoretical mean temperature of -20°C for the condition of zero CO2, this model indicating substantial saturation of the greenhouse effect such that mean temperatures would not exceed 18.5°C even at atmospheric concentrations of 4,000ppm. These findings are based on actual data and thus are empirical in nature, these essentially being at odds with bizarre claims of activists and experts alike for runaway global warming. Runaway warming never happened when Earth experienced levels of 4,000ppm and beyond, and it is not going to happen in future, except in the nightmare visions of some seriously warped people.
What I need to do now is take my willow bat and play a stroke at the googly that is causality. Has mean temperature over the period 1659 – 2021 really been dependent on atmospheric CO2 concentration, or has atmospheric CO2 concentration been dependent on temperature? Or something else entirely, perhaps? We should be able to determine the truth of the matter given we have 363 annual points in our pocket, and we shall start by considering the first order difference.
First What?
The first order difference for a time series sounds fancy but it is simply babble for considering the year-on-year changes. Hence, if atmospheric CO2 was recorded at 320ppm, 324ppm, 326ppm, 323ppm over four years then the first order difference would yield values of +4ppm, +2ppm, -3ppm. If we derive differences for both mean temperature and CO2 we can them plot these out as an X-Y scatterplot, the logic being as follows:
Over on the left we have two scatters that support the notion of CO2 induced warming in that the temperature difference rises when the CO2 difference rises, and the temperature difference falls when the CO2 difference falls (though causality is ambiguous).
On the right we have two scatters that refute the notion of CO2 induced warming in that the temperature difference falls when the CO2 difference rises, and the temperature difference rises when CO2 difference falls.
With that understanding of what we are about to see tucked into our belt let us now grab some real data…