This research aims to develop mitigation and adaptation strategies for greenhouse gas emissions Thailand in accordance with Climate-Smart Agriculture policies. The research employs a mixed-methods approach, integrating both quantitative and qualitative research as a crucial framework for impact analysis and an early warning tool for the government in achieving sustainability. On the quantitative side, an advanced model called the Longitudinal Mediated Moderation Analysis Based on the Fuzzy Autoregressive Hierarchical Process (LMMA-FAHP) model has been developed. This model meets all validity criteria, shows no signs of spuriousness, and outperforms previous models in terms of performance. It is highly suitable for policy formulation and strategic planning to guide the country’s long-term governance toward achieving net-zero emissions by 2065. The findings indicate that the new scenario policy, with an appropriateness rating of over 80%, includes factors such as the clean technology rate, biogas energy, biofertilizers, organic fertilizers, anaerobic digestion rate, biomass energy, biofertilizer rate, renewable energy rate, green material rate, waste biomass, and organic waste treatments. All indicators demonstrate a high sensitivity level. When the new scenario policy is incorporated into future greenhouse gas emissions forecasts (2025–2065), the research reveals a declining growth rate of emissions, reaching 78.51 Mt CO2 Eq., with a growth rate of 11.35%, which remains below the carrying capacity threshold (not exceeding 101.25 Mt CO2 Eq.). Moreover, should the government adopt and integrate these indicators into national governance frameworks, it is projected that greenhouse gas emissions by 2065 could be reduced by as much as 36.65%, significantly exceeding the government’s current reduction target of 20%. This would enable the government to adjust its carbon sequestration strategies more efficiently. Additionally, qualitative research was conducted by engaging stakeholders from the public sector, private sector, and agricultural communities to develop adaptive strategies for future greenhouse gas emissions. If the country follows the research-driven approach outlined in this research, it will lead to effective long-term policy and governance planning, ensuring sustainability for Thailand.