All at Sea? Externalities and Cargo Diversion in the Wake of Brexit
利用英国脱欧作为案例，分析2013-2024年港口数据，发现脱欧导致欧盟-英国滚装货运量下降21%，爱尔兰-英国下降60%，而爱尔兰-法国货运量增加88%，并估算直接航线的碳排放降低约35%，揭示了第三方国家间运输的外部性。
ABSTRACT How does withdrawing from a free trade agreement affect maritime cargo volumes? Are there external effects on freight transport between third‐party countries? Using Brexit as a case study, in a difference‐in‐differences analysis of 2013–2024 port‐level data, I find a 21% decrease in EU‐UK roll‐on roll‐off (Ro‐Ro) volumes, and a 60% decrease in Ireland‐UK volumes. I find an 88% increase in Ireland‐France cargo, indicating a diversion from the UK ‘land‐bridge’ between Ireland and mainland Europe to the direct route. I estimate that emissions would be roughly 35% lower on the direct route, revealing an externality on transport between two third‐party countries.