Evolution of the Climate as an Attributable Complex System with Main Cause

Liaofu Luo, Jun Lv

Attributable complex systems can be classified into two categories: those with a main cause and those without. The climate is an attributable complex system with a main cause, where CO2 concentration serves as the primary fingerprint. The essential dynamics of climate change can be effectively captured through the representation of CO2 concentration. In this study, we analyze global warming in detail, discovering that historical CO2 concentration data can be well described by exponential growth. Extending the simulation of CO2 concentration changes from 2015 to 2500 within the framework of Shared Socioeconomic Pathways (SSPs), we observe a transition from exponential growth to exponential decay in the later stages. To model this shift, we introduce a modified exponential function. Additionally, by accounting for natural climate variability and examining the correlation between global temperature anomalies and CO2 concentrations, we find that this correlation becomes evident only over the long term. Using this relationship and CO2 concentration data, we generate predictions for global temperature anomalies up to 2500, which can be compared with other models in the literature.