Background: The implementation of the Sustainable Development Goals (SDGs) requires much planning and the provision of resources, especially regarding the necessary investments, technologies and infrastructures needed. Yet, it is presently unclear how available these elements are, what gaps exist, what changes have taken place in terms of their availability since the adoption of the SDGs and what their requirements will be in the future. The knowledge gap has become even more concerning because of the impact of the COVID-19 pandemic. Using a bibliometric analysis, an assessment of the global progress of SDG implementation and requirements, identifying challenges through the development of a matrix, and a set of 11 case studies to triangulate the holistic analysis, an assessment of the global progress of the SDGs implementation and the impact of the COVID-19 pandemic on this process was carried out. Results: The findings suggest that the scope and width of resources limitation are currently undermining the implementation of the SDGs. Apart from the fact that the pace of progress has been insufficient, the potential of the SDGs in pursuing sustainability and improving life quality is not fully realised. This trend suggests that a substantial acceleration of the efforts is needed, especially for the five SDGs whose progress since 2015 has not been optimal, namely SDG2, SDG11, SDG13, SDG15, and SDG16, while SDG3, SDG7, SDG9, SDG14, and SDG17 show signs of progress. The case studies showed that different industries have dissimilar effects on achieving the SDGs, with the food sector correlating with 15 SDGs, as opposed to the energy sector correlating with 6 SDGs. Accordingly, the priority level assessment in terms of achieving the SDGs, points to the need to further advance the above-mentioned five SDGs, i.e., 2, 11, 13, 15 and 16. Conclusions: This study fills in a knowledge gap in respect of the current need for and availability of investments, new technologies, and infrastructures to allow countries to pursue the SDGs. It is suggested that this availability is rather limited in specific contexts. In respect of the needs to be addressed, these include resource-related constraints, limited technologies and infrastructures, affecting SDG2, SDG11, SDG13, SDG15, and SDG16, whose progress needs to be enhanced. Since the global progress in the process of implementation of the SDGs depends directly and indirectly on addressing the resource gaps, it is suggested that this topic be further investigated, so that the present imbalances in the three dimensions of sustainable development: the economic, social and environmental, be adequately addressed.

Background: Despite Germany’s world leadership of Energiewende, there have been mounting challenges, such as the slowdown of German renewable energy growth since 2017, when the Merkel administration dramatically changed the German renewable energy promotion policy from feed-in tariffs to competitive auctions. These challenges pose important research questions about whether and how an emerging urban expansion of Energiewende can serve as a vital solution to counteract the challenges to the energy transition. Answering these research questions provides a unique opportunity to explore the academic and historic foundations of the energy transition and its urban expansion, the emerging events that exemplify urban expansion, and the viable solutions this growing trend of urban expansion might be able to provide to the challenges to the German energy transition. Methods: This paper conducted visual and manual bibliometric analyses, examined the results of case studies, and reviewed secondary literature and data on urban expansion of German Energiewende. Results: By analyzing the bibliometric and investigative results, this paper identified political, socioeconomic, and technological challenges to Energiewende and a new trend of solar energy expansion in German cities aimed at meeting Germany’s carbon neutrality targets by 2045. The new trend of the urban expansion of the German energy transition manifests itself in the focused research efforts on identifying the vast untapped potential on new building rooftop areas in most populous German cities and/or detached and two-family houses in Germany and the recent booming of building-related solar PV and heating mandates in German cities and states, the expanding solar heating and cooling systems, and the government policy support at various levels in this urban expansion through aggressively strengthening climate and renewable energy targets. Conclusions: In search for answers to the recent challenges of Energiewende in Germany, this paper conducted both visual and manual bibliometric analyses and applied desk research and reviews of secondary literature and data. This paper found an emerging trend of the urban expansion of Energiewende, including the awareness of the vast potential and gap of urban solarization and the enhanced urban municipal policies, actors, actions, and accomplishments of exploiting this potential. These findings were based on academic knowledge on the German energy transition and contribute to expanding this academic knowledge. To help more effectively exploit the vast potential in solarizing all German cities, especially the largest ones, this study recommends that further research more closely track the progress of this trend and apply more quantitative tools and approaches in future tracking.

Rivers are important ecosystems, vital to the livelihoods of hundreds of millions of humans and other species. Despite their environmental, social, and economic importance, current use of rivers is unsustainable, due to a combination of solid waste and high levels of pollutants. Plastic materials are among the most predominant of such pollutants. Based on the need for additional research in this area, this study examines pressures put to rivers and explores trends related to riverine plastic pollution, with a focus on Asia. Apart from the bibliometric analysis, and relying on the collected information, examples describing the drivers of riverine plastic pollution in a sample of Asian countries are described, outlining the specific problem and its scope. Among some of the results obtained from it, mention can be made to the fact that much of the literature focuses on plastic pollution as a whole and less on one of its most significant ramifications, namely microplastics. Additionally, there is a need related to data availability on riverine plastic data and improving the understanding of transport mechanisms in relation to riverine plastic emission into the ocean. The results from this study illustrate the significance of the problems posed by plastic waste to Asian rivers and point out the fact that there are still significant gaps in respect of regulations and standards, which prevent improvements that are highlighted in this study. Based on the results of this bibliometric assessment, specific measures via which levels of riverine plastic pollution may be reduced are presented, bringing relevant new insights on this topic beyond the existing reviews.