Over the past 30 years, there have been growing concerns on the environmental impacts of maritime transportation, which have attracted great attention from both academia and practitioners. Understanding developments in this area can help guide future research. We conducted a comprehensive review of green shipping research, comprising 213 papers published in transportation journals in SSCI of 2017 over the period 1988–2017. We find that research on green shipping has increased greatly since 2012, accounting for 77.5% of the reviewed papers. The main focus today on green shipping was on air pollution, and the classification of green shipping practice, such as technical measures, operational options, market-based measures, and recycling and reusing, is becoming clear. According to the existing studies, future research on green shipping must strengthen technology research to not only solve practical problems, but also to establish a theoretical green shipping system. Moreover, researchers from different countries could cooperate with each other to give effective suggestions on setting standards and laws of green shipping. Finally, we identify the future research themes will focus on setting up green shipping system and legislation and policy.

With the development of new technologies, smart shipping makes possible one system that connects ports and ships to help stakeholders make decisions with greater efficiency, minimized costs and smaller ecological footprints. However, smart shipping is at the preliminary stage, and the related literature on smart shipping systems or domains is still lacking. To understand and develop smart shipping, our study intends to establish an index system based on the literature review and the Delphi method. Consequently, the system, which includes four first-level indexes, 17 second-level indexes, and 61 third-level indexes, is established. As the main domains, smart waterways, smart ports, smart ships, and maritime intelligence compose the smart shipping system. Among these four domains, the coordinated opinion of experts proposes that smart ports are very important for achieving smart shipping. Furthermore, based on the means of each index, indexes with higher scores can help stakeholders who want to participate in smart shipping make decisions.

An appropriate description of freight rate behaviors is important to maritime forecasting and portfolio diversification in shipping freight markets. We employ general autoregressive conditional heteroscedasticity-copula models to capture the dynamics and interdependencies among shipping freight rates. Using weekly data from 5 January 2002 to 24 March 2018, our main findings are first, Granger causality tests confirm the presence of one-way causality running from the dry bulk and the clean tanker freight rate returns to the container and the dirty tanker freight rate returns, respectively. Second, volatility persistence exists in individual shipping freight market and, in particular, it is much less persistent in the clean tanker freight market. Third, nonlinear dynamic interdependencies among freight rate returns are captured by performing time-varying copulas. The results not only deepen our understanding of freight rate behaviors but also offer new insights into portfolio diversification and risk management in the shipping freight markets.