Background: This paper has reviewed the international research on the terms “climate change” and “human migration” from 1999 to 2019. To this end, a bibliometric and a cluster analysis by fractional accounting have been carried out using two of the most important databases: Web of Science (WoS) and Scopus. The research found and studied 140 documents from WoS Core Collection and 193 from Scopus. Results: The results show a continual increase in the number of articles published and citations received during the whole period studied. The U.S., U.K., Germany and China have been shown to be the most productive countries and there is a predominance of North American organizations supporting and fostering research on these topics. Conclusions: The main contribution of this article is the analysis of new tendencies. The trend shows a transition from concepts such as vulnerability, climate change, land degradation, refugees and security to others such as concepts such as international migration, climate justice, sustainability, human rights and disaster risk reduction. Future research in this field should address the comparison of results from research focused on human beings to a focus on other living beings.

Tourism related to the sea and boating activities is becoming increasingly popular and revolves around a range of leisure, water sports, nautical or other maritime activities. This article studies the main scientific contributions in this area, bearing in mind the complexity of finding a suitable definition of this concept. Hence, the aim of this paper is to analyze the scientific production from 1986 to 2020 in impact journals of the terms “nautical tourism”, “maritime tourism” and “marine tourism” considering the following variables: number of documents, number of articles, period being studied, Hirsch citations and index. The results show an increasing trend in terms of both the number of published articles and citations publications from 2007 onwards and the review of the literature raises the need to define a new concept: “blue tourism”. Future trends in research include terms such as tourist ports, quality of websites and blue economy.

Since the eighties, the concern for sustainability has been increasing from several dimensions and depending on different socio-economic, political, geographical and cultural factors. In the last few years, local development has incorporated the concept of sustainability, as part of the United Nations’ Sustainable Development Goals strategy, highlighting the relevance of this process. The purpose of this research is to show the state of the art of this subject, for what a bibliometric analysis has been carried out based on the two most important online databases: Web of Science and Scopus. This article identifies the latest trends that characterize the concept of sustainable local development, where resilience is the new perspective to include in the variables that influence the development of territories. The results show a positive trend in this field of research, with both the number of articles published and citations increasing exponentially in the last ten years. In addition, the analysis of keywords has shown a tendency towards terms such as resilience, rural tourism or ecological agriculture. In essence, the concept has reached such a point that it is necessary to establish new mechanisms that soften and even negate the economic disruption caused by globalization.

This paper has reviewed the international research on the interactions between the Economy, Energy, and Environment (3E) in the 21st century. For this purpose, a bibliometric and cluster analysis by fractional accounting has been carried out based on the two most important databases: Web of Science (WoS) and Scopus. The research found and studied 2230 documents from the WoS Core Collection and 3,149 from Scopus. The results show a continuous increase in the number of articles that were published and citations during the whole period. They also showed that China and the United States (U.S.) were the most productive countries and there was a predominance of Asian organizations supporting and fostering researches. The main contribution of this article is the analysis of keywords from 2001 to 2018. The trends show that the main common elements are sustainable development and sustainability and they also include CO₂ emissions and consumption. Future research in this field should address the energy transition issue in the area of sustainable development by adapting it to the restrictions of this economic model.

This paper has reviewed the international literature on the explaining factors of efficiency of local governments from 1990 to June 2019. The main objective of this work is to explore the dynamics of the development of this line of research, not only to find out the terminology preferences that have dominated the pre‐ and post‐crisis period in this field but also to identify the latest worldwide research trends. For this purpose, a bibliometric and cluster analysis by fractional accounting has been carried out. The principal result of this article is twofold. First, during the whole period 1990–2019, the ranking of the most used terms is dominated by the keywords of the publications in the second subperiod 2008–2019. Second, the analysis of the latest trends, which has been extended until June 2021, shows that in recent years, the study of the determinants of local government efficiency has revolved around concepts related to environmental issues and new forms of local management.

Green infrastructure (GI) is a nature-based solution that encompasses all actions that rely on ecosystems and the services they provide to respond to various societal challenges such as climate change, food security or disaster risk. The objective of this work is to analyze the state of the art and latest trends in research on GI related to the water cycle for the period 2002–2019. For this purpose, a bibliometric study is carried out taking as reference the two most important scientific databases, Web of Science (WoS) and Scopus. The results show that, as of 2013, there is an exponential increase in the number of publications. This is due to the fact that significant regions of the planet, such as Europe, have adopted strategies aimed at promoting the use of GI since 2013. The keyword analysis points out that ecosystem services is the most relevant concept, which shows the capacity of these infrastructures to facilitate multiple goods and services related to the water cycle. New lines of research are opened up which are based on the analysis of other elements of GI related to water, such as groundwater.