Glossary
Green shipping refers to efforts across the maritime industry to reduce the environmental impact of global shipping. The concept encompasses a wide range of approaches aimed at improving how ships are designed, powered, operated, and regulated to lower emissions and enhance environmental performance across maritime transport.
Green shipping spans several areas of activity within the industry, including advances in vessel technology, the adoption of lower-carbon and alternative marine fuels, improvements in ship operations and voyage management, systems for monitoring and reporting emissions, as well as adherence to international and regional environmental regulations (e.g. FuelEU Maritime, IMO 2023 GHG Strategy). Together, these elements shape how shipping companies and regulators address the environmental footprint of commercial maritime activity.
The push toward greener shipping has accelerated as the environmental impact of maritime transport has come under greater scrutiny from regulators, cargo owners, and financial institutions. While shipping remains the most carbon-efficient mode of large-scale freight transport, the sector still represents a significant source of global greenhouse gas emissions.
At the same time, overall emissions from maritime transport have continued to rise alongside global trade volumes. Between 2019 and 2024, global maritime transport emissions increased from approximately 889 million tonnes of CO₂ to around 973 million tonnes, a rise of approximately9%.Alongside these trends, the International Maritime Organization (IMO) has revised its 2018 decarbonization strategy through the 2023 IMO Revised Strategy (MEPC 80), setting a target for international shipping to reach net-zero greenhouse gas emissions by or around 2050, supported by interim reduction targets of 20–30% by 2030 and 70–80% by 2040, both measured against a 2008 baseline.
Taken together, these regulatory, commercial, and environmental pressures have moved green shipping from a peripheral sustainability discussion to a central issue in the future development of the global maritime industry.
One of the most widely discussed pathways is the transition toward lower-carbon marine fuels. While liquefied natural gas (LNG), methanol, and advanced biofuels are already in commercial use across various fleet segments, fuels such as ammonia and hydrogen remain at the pilot and early development stage. And although these fuels have the potential to reduce greenhouse gas emissions compared with conventional heavy fuel oil, their adoption depends on the development of global bunkering infrastructure, vessel compatibility, and evolving safety standards.
Another important pathway focuses on improving the energy efficiency of ships through advances in design and engineering. Shipbuilders and operators are implementing technologies such as optimized hull forms, advanced hull coatings, air lubrication systems, and energy-saving propulsion devices to reduce hydrodynamic resistance and improve fuel efficiency. In addition, some vessels are incorporating wind-assisted propulsion systems (WAPS), such as rotor sails and rigid sails, that allow wind energy to supplement engine power during voyages.
Operational practices also play a role in reducing fuel consumption and emissions across the global fleet. Measures such as speed management, optimized voyage planning, and weather routing help vessels maintain efficient sailing profiles over long distances. By reducing unnecessary deviations and maintaining stable propulsion loads, these practices can improve overall energy efficiency without requiring structural changes to the vessel.
Environmental performance in shipping is increasingly evaluated through standardized reporting frameworks. Systems such as the Energy Efficiency Existing Ship Index (EEXI), the Carbon Intensity Indicator (CII), and the EU Monitoring, Reporting and Verification (MRV) regulation require vessels to measure and report fuel consumption and emissions data. In addition, policy mechanisms such as the EU Emissions Trading System (EU ETS) are introducing financial accountability for emissions, reinforcing the importance of accurate monitoring and transparency.
Green shipping also depends on developments beyond the vessel itself. Ports, energy providers, and maritime authorities are investing in shore power systems, alternative fuel bunkering infrastructure, and port electrification to support lower-emission operations. At the same time, initiatives such as green shipping corridors are being developed to accelerate the adoption of cleaner fuels and technologies along specific trade routes through coordinated efforts between shipping companies, ports, and regulators.
The overarching framework for ship air pollution and emissions regulation is MARPOL Annex VI, the IMO convention establishing international limits on sulphur oxide (SOx) and nitrogen oxide (NOx) emissions from ships. It also provides the parent framework under which the key greenhouse gas measures covered in this section have been developed and enforced.
Green shipping and maritime decarbonization are related but distinct.
| Area | Decarbonization Strategy | Green Shipping |
|---|---|---|
| Focus | Structural transition to alternative fuels and propulsion technologies. | Operational optimization within the existing vessel configuration. |
| Investment horizon | Long-cycle vessel, fuel, and infrastructure investment. | Daily operational and routing decisions. |
| Timeline | Multi-decade transition planning. | Immediate and continuous efficiency gains. |
| Primary lever | Capital allocation and fleet renewal. | Execution discipline and performance management. |
An efficiency-first approach lets operators stabilize emissions performance within their existing vessel configurations – using onboard data and operational intelligence.
Orca AI improves voyage execution by giving crews automated situational awareness and the data to make real-time route decisions. The shift from static planning to real-time maritime route optimization enables crews to maintain steadier speed profiles and avoid fuel-intensive corrective maneuvers.
Execution stability produces measurable results. In the Ionic fleet deployment, our platform contributed to a 3% reduction in fuel consumption while improving safety performance in challenging waters. Similar gains were recorded in Seaspan’s global fleet operations, where reduced maneuver volatility translated into lower fuel costs.
Across client fleets in 2023, this approach contributed to approximately 172,716 tonnes of CO₂ reduction, driven by fewer sharp maneuvers, reduced speed drops, and a lower number of potential incidents.
Stabilizing propulsion patterns and reducing operational volatility positively influence CII performance over time. Consistent voyage execution strengthens emissions reporting integrity and supports alignment with FuelEU Maritime regulatory requirements.
