From global to national scenarios: Exploring carbon emissions to 2050

The world is still following an unsustainable development pathway, facing great challenges in global CO2 emissions reduction in the coming decades. In this study, we used Kaya identity model to project CO2 emissions. We considered three main scenarios (business-as-usual, BAU; post-Copenhagen-Paris, PCP; deglobalization (COVID-19), DGC), which explored different pathways for CO2 emissions of fuel combustion to 2050 from global to national level. The results show that industrialized countries have been the largest contributors to global CO2 emissions, but some emerging economies are now among the top emitters in absolute terms. For countries at all stages of development, it's going to be important to reduce the trajectory of global greenhouse gas emissions and boost resilience to mounting climate impacts. Among the global, regional, the United States and China CO2 emissions reduction scenarios, the PCP scenario is the best CO2 emissions reduction pathway, in this scenario global CO2 emissions will reach a peak by 2029 (31.813 Gt). Renewable energy leads the transition to a lower-carbon energy mix. The COVID-19 pandemic resulted in the largest-ever decline in global emissions.