# Sustainability Challenges in Maritime Transport and Logistics Industry and Its Way Ahead
## 2 Sustainability Issues in Shipping, Port and Maritime Logistics  
The eight choice papers for this Special Issue have been collected from open invitation through the Sustainability journal website and two international conferences: The 1 st international conference on Yangtze-River Research Innovation and Belt, held in Ocean College, Zhejiang University in Zhoushan City, China on 2-5 December 2018 and the 3 rd International Conference on the Belt and Road Initiative in association with the Asian Logistics Round Table, held in Vietnam RMIT University in Ho Chi Minh City, Vietnam on 24-26 June 2018. [PERSON] et al. (Contribution 1) conducted a comprehensive literature review of sustainability published in maritime-related journals between 1993 and 2017, applying a generative probabilistic text-mining technique, called latent Dirichlet allocation (LDA) [26]. The journals cover transportation, logistics, shipping, and port-related topics and are listed on the science citation index (SCI), science citation index expanded (SCIE) and social science citation index (SSCI). A total of 155 papers were collected for the study. LDA can capture topics on shipping, port, maritime logistics issues in sustainability in terms of keywords frequency, their betweenness centrality, their network for co-occurrence of the papers, and co-authorship by country, affiliation, and collaboration between authors, respectively. One interesting result in this paper is that there are 18 high-frequency keywords above five occurrences which are related to maritime sustainability. Leaving aside sustainability, the term \"management\" has the highest occurrences, followed by \"port,\" \"emission,\" \"impact,\" and \"performance.\" For the shipping and port sector, these issues are related to green ports/shipping, carbon emission/climate change and region-specific environmental regulation/management. For the maritime logistics sector, sustainability issues are generally related to achieving optimal logistics systems, sustainable supply chain design, and service quality management. Another interesting test result shows that, recently, the keywords in sustainability studies in maritime transport and logistics have considered governance, corporate social responsibility, and supply chain management. Therefore, it can be said that this paper contributes to figuring out research trends and research networks in sustainability in maritime transport and logistics over the last 25 years using a solid technique, LDA. Having considered both trade-off analysis and environmental policy intervention analysis, [PERSON] et al. (Contribution 2) developed a comprehensive decision framework for a port-hinterland distribution network in the Yangtze River Economic Belt (YREB) encompassing road, railway, and inland waterways with a three-mode hybrid port-hinterland intermodal distribution network [27]. To minimize logistics costs and CO2 emissions generation, the authors designed a bi-objective decision framework to deal with policy intervention scenarios, taking into account emissions control policies, taxation policy, and emissions trading schemes. The decision framework developed in their paper contributes to offering comprehensive insights for shippers on strategic decisions about optimized intermodal and terminal, and flow distribution under various emissions control policies. The test results show that the transport flows on direct road from inland cities to gateway ports are insensitive to all policy intervention scenarios and that rail transport in the integration of road, railway, and waterway modes have more benefits than other transport modes under all policy intervention scenarios. It implies that policymakers should consider the conflict between logistics costs and carbon emissions under each policy intervention scenario. This study is unique because it is not replicated in the two previous special issues.