A Long-Term CO₂ Emission Forecasting Under Sustainability Policy Using an Advanced Model Complementing the PAARIMAX Framework

The purpose of this research is to develop an advanced model to serve as a strategic tool for the Thailand government in managing the country and to propose ways for the government to exercise state power through proactive measures to address governance gaps and ensure long-term sustainability. This research employs a mixed-methods approach. The research methodology involved the following stages: (1) Quantitative research was conducted by creating the best model, which involved conducting path analysis based on an autoregressive integrated moving average with an exogenous variable model (PAARIMAX (1,1,1)). (2) The results of the quantitative research were optimized to facilitate additional qualitative research in order to identify appropriate ways of using state power for long-term sustainability in country management. The study’s findings suggest that the government will need to exercise its state power in the governance of the country through the development of a long-term national management plan (2024–2043). This plan involves the establishment of a new scenario policy wherein a minimum of 35% clean technology and green materials must be utilized within the economic sector. This is primarily due to their significant impact on environmental change. Furthermore, the government should exercise its state power to mandate an immediate reduction in energy consumption of 50%, achieved through the immediate adoption of renewable energy sources. This research utilized the results derived from the PAARIMAX model to conduct further qualitative analysis to fill the gaps, enhance the value of the quantitative research, and align it more effectively with the context of practical application. The study found that the proactive measures suggested by stakeholders must be implemented alongside the urgent establishment of new scenario policies, including for charges and taxes, subsidies and concession taxes, deposit refund systems, and property rights and market creation.