COP30: Maritime Transport

Recommendations

• Increase energy efficiency. Establish requirements and provide support for energy-saving technologies and optimised ship designs.
• Support green fuels. Use contracts for difference to close the cost gap between fossil and low- or zero-carbon alternatives.
• Develop green corridors. Establish ports and infrastructure for zero-emission transport.
• Ensure climate-friendly refrigeration solutions. Support the development of natural refrigerants for use on ships.

Current situation

The maritime sector is responsible for about 3 percent of global greenhouse gas emissions. Decarbonising shipping is therefore a key step in achieving both national and international climate targets. In July 2023, the International Maritime Organization (IMO) reached agreement on a strategy for reducing greenhouse gas emissions from ships, with targets of 20–30 percent reduction by 2030, 70–80 percent by 2040, and net-zero by 2050, compared to 2008 levels. This was followed by the introduction of the IMO Net-Zero Framework in 2025.

The challenge lies in the implementation. Green fuels such as hydrogen, ammonia, methanol, and biofuels are currently expensive, space-demanding, and not yet available in sufficient volumes. At the same time, shipping is a cost-driven industry, and low- and zero-emission solutions still compete poorly economically with fossil alternatives. This means that development must be supported by both policy, economic instruments and technological development. Energy efficiency also plays a crucial role. Measures such as improved logistics planning, optimal route management, modern hull design, and new propulsion systems can substantially reduce fuel consumption.

For temperature-controlled cargo, on-board refrigeration systems are essential. Today, most systems use high-GWP refrigerants — 96 percent of refrigerated containers use R134a, which has a global warming potential (GWP) of 1430. There is a risk that operators will switch to low-GWP refrigerants classified as PFAS, which pose undesirable health and environmental effects. Use of natural refrigerants can solve this through development of safe and energy efficient systems.

Solutions

The IMO’s greenhouse gas reduction strategy opens the door to implementing a regulatory framework that can drive transformation within the maritime sector IMO regulations are key for international shipping, which dominates global maritime emissions.

Cargo owner demands and regional regulations (e.g. Northern Europe) can accelerate change, as shipowners and operators prefer vessels that can sail in as many parts of the world as possible. This provides regions (for example Northern Europe) with an opportunity to influence global development by introducing regional rules and restrictions. The basis for these actions is better teamwork among all parts of the shipping industry to create a solid foundation for investment. This involves working together between cargo owners and shipping companies, funding projects that reduce emissions in shipping, coordinating between transport operators and ports to reduce waiting times, aligning different transport methods in the supply chain, and working together to ensure fuel is available, such as through green shipping corridors.

Energy efficiency can be improved in several ways and should be backed by research in various areas. This includes better ship design using modern sail technology, improved planning to maximize the load of cargo ships, scheduling arrivals at ports to allow for slower speeds, and using efficient electric engines with batteries (which applies mainly to specialized ships, not the main deep-sea fleet). Cleaning the hull to reduce drag is also important, along with creating new antifouling coatings or using air lubrication systems to decrease resistance.

The maritime sector is highly diverse, and there is therefore a need for multiple emission-free concepts that can be adapted to different vessel types. Numerous technologies and systems already exist for various green fuels, but further development and scaling are required to lower costs and accelerate the transition. Increased investment in renewable power generation is also critical to produce sufficient volumes of low-carbon fuels.

On-board carbon capture and storage (CCS) can be an alternative to low- or zero-emission fuels. When combined with carbon-based zero-emission fuels such as biofuels, this can even deliver net-negative emissions. On-board CCS technology already exists, but effective CO₂ reception and handling chains must be established to make it a viable solution. To cut emissions from refrigerated maritime transport, we must focus on safe, energy-efficient refrigeration using natural refrigerants. This involves developing new systems tailored for maritime conditions that meet climate and safety standards. Global shipping operations face temperature ranges from –30 °C to +50 °C, making this challenging. Public support for pilot projects and technology standardization is vital for progress. It is also important to require refrigerants with low Global Warming Potential (GWP) and no PFAS emissions to avoid health and environmental issues. Adopting natural refrigerants is the best approach. By combining innovation with clear regulations, refrigerated transport can significantly contribute to the maritime sector’s green transition.