An Ideal yet Highly Accurate Model Correlating Global Average Temperature to Excess CO₂-Emissions

The causality of preceding atmospheric excess-to-equilibrium CO₂-amounts and trailing system temperature increase is captured in terms of the ideal gas law, equilibrium thermodynamics and transition state theory for the first time: the model’s performance is excellent, publicly available global mean temperature data from 1880 (13.58 °C / 290.7 ppm) to April 2021 (14.49 °C / 416.2 ppm) are reproduced at less than ±2 % deviation. Eight future global mean temperatures for atmospheric CO₂-levels between 450 ppm and 7000 ppm are extrapolated and an empiric expression of the relation is derived. The model’s ideal nature allows adaption for other greenhouse gases and provides a reference for conclusions about the energetic weighting and the wider significance of the CO₂-based proportion in the total Greenhouse effect.