Gravity in the sky: Decoding bilateral carbon flows from aviation under the global climate governance scheme CORSIA

This study investigates the determinants of bilateral aviation-related carbon emissions by integrating a gravity modeling framework with a difference-in-differences (DiD) approach. Using disaggregated emissions data covering 2019-2023, the analysis reveals that macroeconomic size, particularly GDP, remains the primary driver of international aviation emissions. Notable asymmetries are identified, with destination countries exerting stronger effects than origin countries, and population size dampening emissions where access to air travel remains limited. Temporal dynamics show a sharp decline in emissions during the COVID-19 pandemic, followed by a gradual resurgence by 2023. Among CORSIA participant countries, emissions initially declined but later increased, surpassing 2019 levels in some cases, especially in the subject-to-offsetting dataset. This pattern suggests that early reductions were largely circumstantial and casts doubt on the long-term effectiveness of voluntary offsetting schemes. Additionally, the analysis highlights the significant role of flight frequency at the origin country in shaping emission flows, pointing to the importance of supply-side operational factors. Within CORSIA members, GDP's influence on emissions becomes more pronounced compared to the overall sample, while the effects of population and distance diminish. These findings collectively underline the necessity for systemic, enforceable, and supply-focused mitigation strategies to achieve sustainable aviation decarbonization.