Ocean-based Solutions for Clean Shipping: Environmental Performance of Emerging Marine Fuels

Shipping is fundamental to global trade, transporting over 80% of the world’s merchandise. However, the sector is a significant source of environmental pressure, accounting for approximately 3% of global CO₂ emissions as well as substantial releases of sulfur oxides (SOx), nitrogen oxides (NOx), and particulate matter. These pollutants degrade air quality and have adverse impacts on marine ecosystems. In response, the International Maritime Organization (IMO) has set ambitious targets—including a 50% reduction in greenhouse gas (GHG) emissions by 2050 (compared to 2008)—spurring interest in low- and zero-carbon alternatives to traditional marine fuels. Emerging options such as green ammonia, hydrogen, methanol, and advanced biofuels are increasingly recognized as crucial for achieving decarbonization goals. However, their environmental performance, including life cycle GHG emissions, pollutant releases, and potential ecological impacts (from fuel production, use, and possible accidental release), remains insufficiently understood. Comprehensive assessment is urgently needed to inform sustainable, ocean-based solutions for cleaner shipping.

This Research Topic seeks to advance understanding of the environmental sustainability of clean shipping through ocean-based solutions. The focus is on evaluating the environmental performance of emerging marine fuels—including green ammonia, hydrogen, methanol, and advanced biofuels—across their full life cycles, encompassing GHG emissions, local air pollutants, and ecological risks in various operational contexts. Special attention will be given to the influence of anthropogenic factors such as production methods, supply chain logistics, regulatory environments, and policy interventions on these fuels’ environmental outcomes. By clarifying how these alternative fuels and related human activities interact with marine ecosystems, this collection aims to provide a scientific basis for robust, fuel-based decarbonization strategies. Ultimately, this will guide the effective transition to clean shipping and help safeguard marine ecosystem integrity as part of a sustainable blue economy.

We invite original research articles, reviews, and case studies addressing the environmental, technical, economic, and policy aspects of emerging marine fuels in the context of clean shipping and marine ecosystem health. Manuscripts employing life cycle assessment, modeling, field studies, or interdisciplinary approaches are particularly welcome. Topics of interest include (but are not limited to):

• Decarbonization pathways and scenarios for sustainable marine futures

• Holistic environmental assessments of next-generation marine fuels (GHG, SOx, NOx, particulates)

• Dynamic evaluation and optimization of alternative marine fuel systems

• Policy, economic, and technical drivers shaping the adoption of novel marine fuels

• Impacts of alternative fuel supply chains on marine ecosystems and biodiversity

• Strategies for resilient and environmentally sound shipping within ecosystem-based management frameworks

We welcome both original research and comprehensive review papers that offer new insights and practical solutions for the clean shipping transition and its ecological implications.