Key Takeaways & Executive Findings
- •• • Transportation and distribution accounts for 88.73% of positive carbon emissions in the ship supply chain life cycle, making it the primary target for decarbonization efforts. • • Scrapping and recycling provides a carbon offset benefit of 6.77%, demonstrating the importance of circular economy practices in reducing net emissions. • • Among five reduction scenarios, green logistics achieves an 18.44% reduction efficiency, second only to the comprehensive scenario (20.95%), and is identified as the core pathway for decarbonization. • • Sensitivity analysis shows that optimizing the LNG carbon emission factor within the green logistics scenario can further enhance reduction effects, highlighting the role of fuel choice and efficiency.
Abstract
The shipping industry's carbon emissions have drawn increasing attention. This study quantifies the carbon footprint of ship supply chains across their life cycle to identify key emission stages and reduction potentials, promoting green transformation. Based on life-cycle theory and using process analysis, a carbon footprint assessment model was constructed covering raw material acquisition, construction and assembly, transportation and distribution, and scrapping and recycling. The model was applied to a case ship, followed by multi-scenario and sensitivity analyses. Results show that the transportation and distribution stage is the dominant source of positive emissions, accounting for 88.73% of the total, while the scrapping and recycling stage provides a carbon offset benefit of 6.77%. Among five emission reduction scenarios—low-carbon materials, green energy, green logistics, circular economy, and comprehensive low-carbon—the reduction efficiencies are 2.02%, 0.06%, 18.44%, 0.42%, and 20.95%, respectively, indicating that green logistics is the core pathway for decarbonizing ship supply chains. Under the green logistics scenario, optimizing the LNG carbon emission factor yields more significant reduction effects. This study provides a life-cycle perspective on the carbon footprint structure of ship supply chains, offering theoretical references for identifying key reduction links and optimizing low-carbon technology pathways.
1. Introduction
The maritime shipping industry, responsible for approximately 80% of global freight volume and 70% of cargo value, faces mounting pressure to reduce greenhouse gas emissions. Despite being the most energy-efficient transport mode, the sector contributes nearly 3% of global emissions, with a 20% increase over the past decade. The International Maritime Organization's initial strategy targets a 40% reduction in carbon intensity by 2030 and 70% by 2050 relative to 2008 levels. However, existing carbon footprint assessments often focus narrowly on fuel-related emissions or lack a comprehensive supply chain perspective, failing to capture the full life-cycle impacts and the potential of circular economy practices.
This study addresses these gaps by employing a process-based life-cycle assessment to model the carbon footprint of ship supply chains from raw material extraction to end-of-life recycling. By integrating four core supply chain actors—raw material suppliers, shipyards, logistics providers, and recycling centers—the model quantifies emissions at each stage and evaluates reduction scenarios. The findings reveal that transportation and distribution dominate emissions, while recycling offers significant offsets. This approach provides a holistic framework for identifying key reduction levers and guiding policy and industry decisions toward sustainable shipping.
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HAN Zinuo, LIN Shuangjiao, PAN Fubin (2026). Life-Cycle Carbon Footprint Assessment and Emission Reduction Strategy Analysis of Ship Supply Chains. Chinese Journal of Environmental Engineering. https://doi.org/10.12030/j.cjee.202510039
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Frequently Asked Questions
What is the functional unit and system boundary of the carbon footprint model?
The functional unit is a single ship over its 25-year design life. The system boundary follows a 'cradle-to-grave' approach, covering raw material acquisition, construction and assembly, transportation and distribution, and scrapping and recycling. The model includes four core supply chain actors: raw material suppliers, shipyards, logistics providers, and recycling centers.
How does the model account for carbon offsets from recycling?
The scrapping and recycling stage is treated as providing a carbon offset benefit of 6.77% of total positive emissions. This is quantified by considering the avoided emissions from material recycling and energy recovery, which are subtracted from the total life-cycle emissions.
What are the specific reduction efficiencies of the five scenarios?
The reduction efficiencies are: low-carbon materials 2.02%, green energy 0.06%, green logistics 18.44%, circular economy 0.42%, and comprehensive low-carbon 20.95%. These are relative to the baseline scenario without additional measures.
Why is green logistics identified as the core reduction pathway?
Green logistics achieves an 18.44% reduction efficiency, second only to the comprehensive scenario, and is more feasible than combining all measures. It includes optimizing fuel efficiency, route planning, and logistics operations, which directly target the dominant emission stage (transportation and distribution, 88.73%). Sensitivity analysis further shows that optimizing the LNG carbon emission factor within this scenario can yield even greater reductions.
What are the limitations of the study and future research directions?
The study focuses on a single ship type and may not capture variations across different vessel classes. Future research could expand the model to include more ship types, incorporate dynamic data on technology improvements, and explore policy interventions that facilitate supply chain coordination for emission reduction.
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