Calculation of global warming limitation due to peak oil, gas & coal

An approximate calculation is done of the carbon-dioxide concentration in the earth’s atmosphere due to burning fossil fuels: coal, crude oil and natural gas. Since these are finite resources and the peak date for crude-oil extraction is about now, the peak date for natural-gas extraction will be about a decade from now and the peak date for coal extraction will be about year 2060, then carbon-dioxide atmospheric concentration due to burning fossil fuels will peak about year 2110, delayed about 100 years from the combined fossil-fuels emission peak because of the carbon-dioxide residence-time decay in the atmosphere.

Therefore, carbon emissions due to burning fossil fuels cannot increase indefinitely, which is some good news for future global warming. However, the impending decline of fossil-fuels extraction is not good news for societal stability and some unknown slow or future-triggered positive-feedback mechanisms may increase global warming more than the fossil-fuels emissions, non-fossil-fuels emissions and known fast positive-feedback effects.


An implicit assumption in this calculation is that humans will burn up or make chemicals from fossil fuels as fast as they can extract them from the earth. No account is taken in this work of global dimming by atmospheric aerosols, which reduces global average temperature.

Adding an approximate calculation of deforestation and other non-fossil-fuels emissions to the fossil-fuels carbon emissions, assuming that non-fossil-fuels emissions are proportional to change in world population, yields a contribution to CO2 concentration that peaks at about 2025 with somewhat less magnitude than the contribution due to crude-oil burning. The combination of fossil-fuels burning and non-fossil-fuels emissions causes a CO2 concentration peak of about 450 ppmv at about year 2110, which corresponds to a temperature rise above year 2005 of about 0.5