Carbon tax impacts on transport emissions in belt and road trade corridors: A scenario analysis

• Carbon tax scenarios (40–60 RMB/ton) show heterogeneous emission reduction effects. • Integrates transport economics, trade policy, and environmental analysis framework. • Waterway transport most responsive to carbon pricing across BRI trade corridors. • Agricultural goods more sensitive to carbon tax than bulk commodities. • Infrastructure and trade structure critical for carbon tax policy effectiveness. Transport emissions from international trade represent a growing contributor to climate change, creating an urgent need for effective policy interventions. This study evaluates the influence of carbon pricing policies on transport emissions in Belt and Road Initiative countries. Three carbon tax scenarios at levels of 40, 50, and 60 RMB per ton were examined to assess their effects on transport mode selection and emissions across trade corridors. A transport modal competitiveness function that integrates carbon pricing as an environmental cost was constructed to predict emission variations. The results indicate substantial heterogeneity in emission reductions across countries, products, and transport modes. Carbon taxation contributes to emission reductions in several trade flows, such as Malaysian minerals decreasing by 7.6 % and Thai vegetables by 4832 tons. However, some flows exhibit increases due to structural constraints, including Vietnamese salt increasing by 13,567 tons. Waterway transport emerges as the most responsive mode to carbon pricing, although effectiveness differs according to product type and trade route characteristics. Agricultural and perishable goods display greater sensitivity to carbon price adjustments, whereas bulk commodities in rigid supply chains demonstrate limited responsiveness or even adverse outcomes. The study emphasizes that carbon tax effectiveness is contingent upon both transport infrastructure and trade structures. Differentiated policy strategies, supported by infrastructure investment and adoption of low-carbon technologies, are essential for promoting sustainable trade and green development along BRI corridors.