Evaluating global carbon neutrality commitments: An integrated assessment model approach to the 2°C target

This study analyzes the impact of carbon-neutral policies on the global climate and economy using a RICE-2010 model, reflecting climate actions of 184 countries. We investigate scenarios including business-as-usual, nationally determined contributions (NDCs), net zero emissions, and 1.5°C compliance. Our findings show that current emission reduction targets, while significant, fall short of limiting global temperature rise to 2°C by 2300, resulting in a projected warming of approximately 2.48°C, or about 0.48°C above the 2°C target. The analysis reveals that an additional 5 GtCO2e reduction is needed by 2030 to align with the 2°C pathway, with major emitters like China, the US, and India requiring the largest additional efforts. The study highlights that climate change impacts and resilience vary based on the timing and degree of emission reductions. Importantly, the costs and difficulties of achieving carbon neutrality differ among countries, potentially leading to free-rider issues. To address this, we emphasize the need for stricter, cooperative global governance on carbon neutrality. While current policies represent substantial progress, enhanced international cooperation and more ambitious targets are crucial to fully achieve the 2°C goal. This study provides insights for policymakers on the scale of necessary adjustments and the importance of equitable burden-sharing in global climate action.