Shipping is associated with various environmental impacts, such as pollutants discharged to air and sea. Much of this pollution appears to be unregulated, and global emissions from shipping are expected to more than triple between 2020 and 2050. This paper reviews global, national, regional and port-level legislative approaches that have been implemented to reduce emissions of carbon dioxide (CO₂), nitrous oxides (NO_x), sulphur oxides (SO_x) and particulate matter (PM). Policies are identified on the basis of a systematic review of the literature in combination with a detailed analysis of the respective global, national and local policy initiatives. Findings suggest that many policies are voluntary or, in ports, incentive-based; regulatory approaches are largely limited to Emission Control Areas. Policies also focus on efficiencies, they are not concerned with absolute pollutant and greenhouse gas levels. No policies incentivizing or forcing the transition to zero-carbon fuels were identified. As ports can define limits to pollution, for instance by demanding shore power use, they can significantly affect the clean development of the sector. Further legislation will be needed nationally to counterbalance the lack of supranational ambition on pollutants and climate change mitigation.

航运与各种环境影响有关，例如排放到空气和海洋中的污染物。大部分污染似乎不受管制，预计从 2020 年到 2050 年，全球航运排放量将增加两倍以上。 本文回顾了为减少二氧化碳排放而实施的全球、国家、区域和港口级立法方法（ CO ₂ )、一氧化二氮 (NO _x )、硫氧化物 (SO _x) 和颗粒物 (PM)。政策是在对文献进行系统回顾的基础上结合对全球、国家和地方政策举措的详细分析来确定的。调查结果表明，许多政策是自愿的，或者在港口是基于激励的；监管方法主要限于排放控制区。政策也关注效率，他们不关心绝对污染物和温室气体水平。没有确定激励或强制向零碳燃料过渡的政策。由于港口可以定义污染限制，例如通过要求使用岸电，它们可以显着影响该行业的清洁发展。需要在全国范围内制定进一步的立法，以抵消在污染物和减缓气候变化方面缺乏超国家雄心的问题。