<p>Climate change is closely related to excessive global greenhouse gas emissions, posing huge challenges to the sustainable development of human society. In this study, the CESM2.1 Earth system model, which simulates the evolution of the natural system, is coupled with the MESSAGE-ix, which represents energy demand and consumption dynamics within the human socio–economic system. The coupling is realized through a loss function and carbon price adjustments, enabling bidirectional feedback and synchronous operation between the two subsystems, thereby forming an integrated human–earth system model (HESM2.0).The coupled human-earth system model (HESM2.0) is used to explore future energy demand and energy related carbon emission changes and to test the model’s ability to simulate future extreme events. The research outcomes indicate that the coupled model has efficiently appraised the future greenhouse gas emissions. Clearly, the requirement for primary energy in developing regions will increase remarkably in the future, and these regions will remain as the areas with high carbon dioxide emissions in the future. Furthermore, the coupled model performs far better in simulating future extreme temperatures than in simulating extreme precipitation and other associated aspects.</p>