By Kenneth Richard on 18. September 2023
“Oddly, while the principal direction suggested by the models is ΔIn[CO₂] → ΔT, the explained variance is impressively low (10-15%) in this direction and impressively high (reaching 90%) in the opposite direction, at ΔT → ΔIn[CO₂].” − Koutsoyiannis et al., 2023
One of the most basic concepts in physics is that causes precede effects and effects follow causes. Determining the directionality sequence is thus essential in any causality analysis.
The assumed CO₂→T causality direction cannot be scientifically supported
The assumption in climate models is that CO₂ causes changes in temperature, or T. More specifically, it is assumed modern global warming has been caused by increases in anthropogenic CO₂ emissions.
However, scientists (Koutsoyiannis et al., 2023) have now expanded upon last year’s 2-part study on stochastics-formulated causality published in The Royal Society (Koutsoyiannis et al., 2022 (1) and Koutsoyiannis et al., 2022 (2)) where they notably contend:
“Clearly the results […] suggest a (mono-directional) potentially causal system with T as the cause and [CO₂] as the effect. Hence the common perception that increasing [CO₂] causes increased T can be excluded as it violates the necessary condition for this causality direction.”
A year later these same authors have again conspicuously demonstrated the assumed CO₂→T causality direction cannot be scientifically supported because observations clearly show that variance in T leads or precedes growth rate variance in CO₂ by 6 or more months.
“All evidence resulting from the analyses suggests a unidirectional, potentially causal link with T [temperature] as the cause and [CO₂] as the effect.”
Observational evidence overrules modeled assumptions, regardless of how compelling or mainstream the conventional wisdom.
Cross-correlation analysis reveals CO₂-causes-warming trend alignment depictions are spurious
Because it is widely assumed human CO₂ emissions are the cause and temperature changes are the effect, tendentiously adjusting the axes on graphs to make it appear that the CO₂ and T trends align (i.e., curve-fitting, as shown in the left-side chart below) has become a popular pursuit for those advancing the anthropogenic global warming narrative.
It can be shown, however, that these trend alignments are spurious. Why? Because in the industrial era there have been periods when temperatures have risen rapidly with negligible CO₂ emissions (1700-1750), and decreasing temperatures while CO₂ emissions were rising (1880-1900, 1950-1970). When including all these counter-alignments together and differencing the time series (cross-correlation), the CO₂→T trend alignment disappears. These non-correlations are clearly shown in the right-side charts below. If there are non-correlations, or if the correlations are spurious, causation cannot be established.
Natural CO₂ emissions induced by warming can be shown to be responsible for rising CO₂ concentrations
Fossil fuel emissions amount to 9.4 GtC/year, which is only 4% of the total CO₂ emissions from all sources. In contrast, nature (respiration, freshwater outgassing, fire, volcanism, etc.) produces CO₂ emissions amounting to 216 GtC/year.
It is assumed that the carbon cycle is, in its natural state (without human interference), in perpetual equilibrium, with emissions from natural sources almost perfectly balanced by natural sinks. This presumption is flawed, however, because nature’s sinks don’t decide to only absorb the 216 GtC/year from natural sources as they simultaneously fail to absorb the 9.4 GtC/year from human activities. The 216 GtC/year from nature and 9.4 GtC/year from fossil fuels are instantaneously combined, and nature’s sinks absorb emissions proportionately from the total, ~225 GtC/year.
In their new paper’s appendix, Koutsoyiannis and colleagues have used basic chemistry to show that outgassing from warming and respiration can be biochemically shown to produce emissions rates of 31.6 GtC/year. This is 3.4 times more than the annual emissions from fossil fuels (9.4 GtC/year). Thus, the observation that temperature may potentially a cause of rising CO₂ concentrations appears to be observationally supportable. A substantial portion of modern CO₂ rise may thus be natural.
Natural mechanisms for warming may include the natural increase in sunshine duration
If rising CO₂ concentrations cannot explain modern warming due to the violation of the requisite causality direction, what can?
As has been detailed extensively in many other observational studies, the recent decline in Earth’s planetary albedo (clouds, aerosols) has been reflecting less solar radiation and increasing sunshine duration in recent decades. This, in turn, warms the surface.
A 0.01 change in planetary albedo can induce a radiative forcing of ±3.4 W/m² (Wielicki et al., 2005).
Koutsoyiannis and colleagues cite CERES data that depict a falling linear trend of -0.0019 per decade in planetary albedo since 2000. This can be shown to have elicited a +1.4 W/m² positive imbalance from incoming shortwave, which is sufficient to explain the modern radiative forcing associated with rising temperatures.
So the warming in recent decades may be natural. The CO₂ increases resulting from the natural warming may be substantially natural too. And these results are observationally supportable.
Given the evidence presented in this new study, the claim that human CO₂ emissions are the cause of modern warming is not observationally supportable.