Ports and shipping are under mounting pressure to decarbonise while maintaining operational efficiency. The challenge is intensified by uneven capabilities: large hubs advance digital and environmental agendas, whereas smaller ports face resource and interoperability gaps. At the same time, new global and EU regulations tighten requirements on fuel quality, lifecycle emissions and shore power use, creating complex compliance landscapes. This dissertation integrates three themes: (i) a comparative synthesis of mitigation options for black carbon emissions in Arctic relevant shipping; (ii) a multi case analysis of port digitalisation to identify conditions for environmental co benefits; and (iii) the design and pilot of a lean self assessment tool enabling small ports to evidence environmental performance. These themes are combined through a place sensitive transition model linking policy drivers, local capabilities and measurement. For Arctic operations, the most effective near term package combines cleaner fuels, particulate filtration and operational optimisation. Digitalisation reduces emissions only when supported by interoperable standards, cyber resilience and governance. The small port tool lowers entry barriers to environmental management, improves comparability and accelerates readiness for certification. Together, these results show that regulatory ambition translates into outcomes only when digital and managerial infrastructures co evolve. Policy makers should complement global decarbonisation measures with geographically targeted controls and fund standards based digital governance. Port authorities should treat digitalisation as a platform strategy and use modular tools to stage environmental management. Researchers should quantify the environmental effect sizes of digital interventions and extend longitudinal trials of lean tools across diverse geographies.