To significantly reduce sulfur oxides emissions from fossil fuel-powered ships, reduce air pollution in ports and slow ocean acidification, the International Maritime Organization (IMO) has imposed the new 0.50%m/m limit (reduced from 3.50%m/m in the past) on sulphur in ships' fuel oil. This has given rise to a host of issues regarding fuel replenishment operations, safe operation management, maritime regulation, and coordinated governance of air and climate. In response to ocean acidification and climate change, regulations on the use of low-sulfur oil or alternative fuels by ships greatly reduce sulfur oxide emissions, but have no significant impact on reducing greenhouse gas emissions. In fact, the refining process for low-sulfur fuels and the use of the gas cleaning system on ships both increase energy consumption and carbon dioxide emissions. To ensure the decarbonization process of shipping industry, there is an urgent need for a conceptual change in global ocean governance so as to promote the coordinated governance of air pollution and climate change. China's conception of "a maritime community with a shared future" provides a new model for global ocean governance. The Chinese government has formulated regulations at different levels to promote the coordinated management of atmospheric pollutants and greenhouse gas emissions. Regarding supervision of sulfur oxide emissions from ships, this study proposes to build a multi-department collaborative supervision mechanism from marine fuel life cycle to enhance sulfur oxide monitoring and risk control capabilities. Specific measures of the proposed supervision mechanism include: the joint supervision of compliant fuel supply, the compliant fuel information disclosure platform, a joint law enforcement mechanism for atmospheric pollution, the ability of intelligent ship exhaust monitoring, and the construction of port power infrastructure.
Switching to ammonia as a marine fuel, with the goal of decarbonisation, can instead create entirely new problems. This is shown in a study from CHALMERS University of Technology in Sweden, where researchers carried out life cycle analyses for batteries and for three electrofuels including ammonia. Eutrophication and acidification are some of the environmental problems that can be traced to the use of ammonia - as well as emissions of laughing gas, which is a very potent greenhouse gas.
Climate change poses a global challenge related to the reduction of pollutant atmospheric emissions and the maritime transportation sector is directly involved, due to its significant impact on the production of Greenhouse Gases and other substances. While established technologies have effectively targeted emissions like Nitrogen Oxides (NOX) and Sulfur Oxides (SOX), the persistence of Carbon dioxide (CO2) emissions represents an ongoing and significant concern. Novel technologies targeting CO2 reduction have been lately studied and proposed for inland applications, and are now being developed for maritime applications. With this regard, the present study explores the potential of Carbon Capture Systems (CCS) to mitigate CO2 emissions produced by cargo ships. While the implementation of CCS faces challenges, including space limitations and logistical complexities, its possible integration onboard marks a significant step in the fight against climate change. The authors propose an innovative approach using a Calcium Hydroxide Ca(OH)2 based CCS, offering the dual benefit of CO2 reduction and the potential resolution of ocean acidification through Calcium carbonate (CaCO3), the final product resulting from the CO2 capture process. Additionally, the study examines the feasibility of the generated product for reuse in industry, promoting a circular economy and addressing environmental issues. This innovative solution underscores the urgent need for transformative measures to reduce maritime emissions, in line with efforts to safeguarding the marine environment and combat climate change.