Nature: "Atmospheric Carbon Dioxide Content As Fuel Gauge"

Ed. - This is open access, and a bit dense in spots, but it's as good an overview of the whole enchilada - GHG output, energy demand growth and what FF energy remains to be exploited using today's technology - as you're going to find within a short paper like this.

Will be coming back this evening for a little more deliberate and time-consuming reading.

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Industrial societies powered by fossil fuels are unsustainable. Murphy et al.1 eloquently articulated the incompatibility of modernity with planetary limits. The schematic view of human energy production (Fig. 1) depicts the alarming reality of the inevitable ending of the fossil fuel era in the not-too-distant future.

One of the arguments questioning the significance of carbon dioxide emissions2 is that atmospheric carbon dioxide concentration in the past far exceeded current and anticipated future levels. Patrick Moore, an ecologist who identifies as a “Greenpeace dropout”3 goes as far as to argue that plants currently suffocate and the “liberation” of fossilized carbon prevented our planet from turning into an iceball3.

Opponents of the climate change agenda often accuse activists of exaggeration and tend to dispute the severity of the consequences of climate change4. Even if the climate change impacts are somewhat overstated, Murphy5 makes an excellent argument by pointing out that the story of the “boy who cried wolf” is largely misunderstood. While this story is often viewed as an example of false alarms, the true moral is that the wolf comes. It is hard to see climate change remain a benign problem when the atmospheric carbon dioxide concentration is rapidly approaching its first doubling since the beginning of the industrial revolution6.

Instead of debunking the arguments disputing the severity of climate change, this paper presents a thought experiment if the upper limit to continued carbon dioxide emission was the atmospheric carbon dioxide concentration around the Cambrian explosion 420 million years ago. Consequently, the paper assumes that the difference in the atmospheric carbon dioxide content during the Cambrian (
)7 vs. the pre-industrial era () was proportional to the fossil fuel reserves, and the rise to the present level () can be interpreted as a fuel gauge showing the exhausted fossil fuel resources. While this interpretation may seem overly simplistic but appears to be consistent with the current understanding of the temporal evolution of the atmospheric carbon dioxide concentration and fossil fuel consumption. Our assumption offers a crude means to put a temporal bound to Fig. 1 and estimate the plausible pathways to exhaust the remaining reserves.

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https://www.nature.com/articles/s41598-025-98459-1