GIS-based analysis of the spatial distribution of CO2 emissions and slow steaming effectiveness in coastal shipping

The sustainability of maritime activities is increasingly gaining interest, with the shipping sector actively focusing on decarbonization efforts. Throughout the years, researchers have considered slow steaming for improving the environmental footprint of maritime networks. In order to assess such strategies’ effectiveness on existing emissions, research also focuses on the accurate estimation of emission inventories. However, there is a significant gap concerning both fields when considering short-sea shipping, especially passenger shipping. Furthermore, while emissions are characterized by spatial aspects in several studies, there is an apparent gap in considering such aspects for detailed analysis purposes rather than only for visualization purposes. In this study, the Greek Coastal Shipping Network (GCSN) is considered, with its emissions estimated using a top-down method, creating a spatial emission inventory used for further spatial analysis for accurate identification of highly polluted areas. Results indicate that ship emissions do not spread homogeneously throughout the GCSN and that targeted interventions are necessary in several areas of the network. The effectiveness of spatially related slow steaming implementations is evaluated and compared with their implementation on the whole network. The study highlights the need for additional future emission mitigation strategies, such as service optimization, network restructuring, continuous emission monitoring, and fleet renewal with more environmentally efficient ships. The study’s aim is to fill the research gap regarding the environmental assessment of passenger shipping and the effects of slow steaming on such networks while presenting an adaptable GIS-based decision support system for enhanced decision-making regarding the environmental efficiency of maritime networks.