A Global Predictive Climate Model

Abstract

Objective: The main objective of the work presented in this article was to obtain a global climate model capable of providing reliable forecasts until 2100 regarding the most Important global parameters of the climate system: atmospheric temperature, ocean temperature, cloud cover, atmospheric albedo, subsidence of the oceanic mixed layer and, finally, oceanic stratification. This, while taking into account the different scenarios defined by the IPCC concerning GHG emissions for the period 2025-2100.

Methods: To achieve this objective, the choice was made to use a discrete model whose implied relationships directly aim to obtain the monthly average global results of the studied parameters, without going through the lower scales. Thus, the difficulties related to the strong non-linearity encountered in most phenomena at lower scales largely disappear and make the model much more deterministic than stochastic, unlike the much more complex GCMs developed by the major climate institutes. The model in question is structured from a recent earlier version (2024) developed by the authors.

Results:
The main results obtained from this modeling are as follows:
•     The radiation budget has been declining since the beginning of the period considered (1955-2100). The radiative forcing is decreasing and tends towards 0.
•     The results vary very little, regardless of the GHG emissions scenarios considered. For the four scenarios considered, the increase in atmospheric
temperature over the period 1955-2100 will be approximately 1.8 ± 0.4°C (95% confidence level).
•     Ergodicity and thermodynamic equilibrium of the current climate system.

Conclusion: To break the thermodynamic equilibrium of the current global climate system and return to a new equilibrium with a cooling trend, we must return to CO2  emissions below 300 ppm (assuming that other GHGs follow a corresponding decline).