Transition towards carbon neutrality: A structured review on current policies and measures in international shipping

Current studies lack a comprehensive understanding of the status of carbon emission reduction in international shipping from the perspectives of policies and measures, which tends to increase uncertainty in policy-making. The study aims to use a structured review approach to systematically collect and analyse carbon reduction policies as well as technical, regulatory, and economic measures in international shipping in recent years to support international shipping carbon neutrality decisions. The results show that most regions are committed to achieving zero emissions by 2050, but the reduction targets of international maritime organizations are lagging; while hydrogen, ammonia and green methanol fuels and ship wind power have a high potential to advance emission reduction, they are still limited by technology, regulation, cost and support; market-based trading measures can reflect emission reduction targets, but carbon prices are not yet mature; other measures also suffer from emissions shifting, low emission reduction potential or unsustainability. Tracking the progress of policies and measures to reduce carbon emissions in international shipping benefits to “know yourself as well as the enemy” for supporting decisions.