Time Series–Based CO₂ Emission Forecasting and Energy Mix Analysis for Net-Zero Transitions: A Multi-Country Study

This study presents a comparative analysis of global energy sources and CO₂ emissions from 2000 to the present, focusing on Nigeria and four countries across four other continents: China, the United States, Brazil and Russia. Multi-source datasets from the IEA, World Bank, and national statistics agencies were harmonized and feature-engineered to capture relationships among energy mix, GDP, population, and policy actions. Using ARIMA/SARIMA, LSTM, and hybrid ensemble forecasting models, the study projects CO₂ emissions trajectories through 2060 under multiple policy and mitigation scenarios. The findings aim to provide actionable insights for national decarbonization strategies and sustainable development planning. The models achieved an average forecasting error of about 6%, revealing that renewable energy adoption policies significantly flatten emission growth for Nigeria and USA under moderate mitigation scenarios.