The purpose of this research was to examine the performance of agrivoltaic systems, which produce crops and electricity simultaneously, by installing stilt-mounted photovoltaic (PV) panels on farmland. As PV power stations enjoy remarkable growth, land occupation with the purpose of establishing solar farms will intensify the competition for land resources between food and clean energy production. The results of this research showed, however, that the stilt-mounted agrivoltaic system can mitigate the trade-off between crop production and clean energy generation even when applied to corn, a typical shade-intolerant crop. The research was conducted at a 100-m² experimental farm with three sub-configurations: no modules (control), low module density, and high module density. In each configuration, 9 stalks/m² were planted 0.5 m apart. The biomass of corn stover grown in the low-density configuration was larger than that of the control configuration by 4.9%. Also, the corn yield per square meter of the low-density configuration was larger than that of the control by 5.6%. The results of this research should encourage more conventional farmers, clean energy producers, and policy makers to consider adopting stilt-mounted PV systems, particularly in areas where land resources are relatively scarce.

This systematic literature review gathers societal vulnerability factors linking climate change and conflict from 53 existing studies. The findings reveal three main points. First, four relevant factors are missing from a previous vulnerability analysis framework proposed by Pearson and Newman: land degradation/land cover, gender, customs, and geographical conditions. Second, two factors, access to technology (e.g., for climate change adaptation) and partially democratic states, are insufficiently studied. Third, classification criteria in the previous framework need revision for accuracy. Considering these points, this study proposes a modified vulnerability analysis framework and offers five suggestions for future research directions in climate security research. First, more qualitative case studies are needed to complement the quantitative work. Second, in particular, cases where conflict was avoided or cooperation was established in high vulnerability areas need further research. Third, further research is needed on understudied factors (e.g., access to technology and partial democracy) and on factors the conventional framework cannot explain (e.g., land degradation/land cover, gender, customs, and geographical conditions). Fourth, no single vulnerability factor leads to conflict in isolation, but only in interaction; their connections must be studied. Finally, case studies are needed on vulnerability factors in countries and regions that have suffered from climate change but have not experienced conflict.

This research paper investigates the evolving defense cooperation between India and Japan in the context of the strategic landscape in the Indo-Pacific region, particularly considering China’s rise. The existing literature recognizes China’s increasing influence as a significant factor in India-Japanese security cooperation, but tends to overlook the dynamics behind India’s shifting stance. The study reveals that India initially hesitated to actively engage in anti-China security cooperation with Japan until the mid-2010s, but later adopted a more proactive partnership. An analysis of policy documents, political speeches, and government records attributes India’s initial reluctance to its commitment to non-alignment and strategic autonomy, its desire to balance relations with both China and Japan, and its domestic political priorities favoring economic development over military expansion or strategic alliances. However, growing concerns over China’s assertiveness, military modernization, a change in political leadership, and the Quad’s development as a regional security platform have prompted India’s attitude shift. The research’s recommendations not only offer a roadmap for India, Japan, and other Indo-Pacific countries with deep economic ties to China, but also help combat China’s military threats to contribute to regional stability and security, address common challenges, and foster a peaceful and prosperous Indo-Pacific region.

This study investigated the scientific progress of climate security studies through a literature review and discussed its risks in East Asia. Climate security refers to the protection of countries and societies from conflicts and riots caused by climate change. As climate change becomes more apparent, climate security has been vigorously debated in the international community. Climate security risks in East Asia, however, are not yet widely discussed. This literature review identified that climate change increases the risk of conflict not only through direct threats to people and societies from extreme weather events and natural disasters, but also indirectly through various pathways, such as shortages of water and other resources, outbreaks of climate migration, disruptions in food production, economic and social disturbances, and geopolitical changes. Considering the climate-conflict pathways identified by the literature review, East Asia may face (1) tensions caused by climate emigrants, (2) conflicts over loss of territories and fishery areas, (3) conflicts caused by water shortage, (4) instability caused by heavy rain and floods, and (5) geopolitical risks of rare earth sourcing, green industrial policies, and the Arctic. East Asian countries need to lower climate security risks in the region through cooperative international measures such as climate change mitigation, vulnerability reduction, and policy dialogue.

This study re-examined the effect of official development assistance (ODA) of five major donor countries (France, Germany, Japan, the United Kingdom, and the United States) on foreign direct investment (FDI) using panel data from 2003 to 2020. In addition to the system Generalized Method of Moments (GMM) with the gravity model, the Granger causality test and impulse response analysis with the panel VAR model was conducted. It was concluded that ODA did not necessarily have an effect on FDI since the 2000s. It is also suggested that the vanguard effect of Japanese ODA, as indicated by some previous studies, appeared mainly in the 1990s and may not be sustainable. The novelty of this study is to verify the effects of the ODA of major donors on FDI using new data from the 2000s onward, especially to reveal that the vanguard effect of Japanese ODA has not been observed since the 2000s. A limitation of this study is to determine only the presence or absence of a general trend at a statistically significant level. Therefore, further research on individual cases is expected to find how ODA has affected the investment decisions of individual companies.

Introduction: The current global food system places a high burden on biodiversity, while food production depends on ecosystem services. This study demonstrated the recent progress in research on the link between food security and biodiversity conservation through a systematic review. based on the Web of Science database. A search for the keywords “food security, biodiversity, conservation” yields a mere 1,968 results, accounting for a negligible 0.76% of the results for “biodiversity.” This suggests that academic interest in the relationship between food security and biodiversity conservation remains minimal. Methods: First, a literature search was conducted using the keywords “food security, biodiversity, conservation.” The keyword search was performed using the Web of Science database, covering the 10-year period from 2015 to 2024. Next, the 115 papers identified through the review were subjected to cluster analysis using the statistical software R, classifying them according to the themes and methodologies addressed in each paper. Results: The first keyword search yields a mere 1,968 results, accounting for a negligible 0.76% of the results for “biodiversity.” This suggests that academic interest in the relationship between food security and biodiversity conservation remains minimal. The results of the cluster analysis classified the 115 papers into five clusters. Discussion: The findings of this study provide insights into the sustainable transformation of food systems. The recent progress in research on the link between food security and biodiversity conservation demonstrates the advancing integration of biophysical-technical and socio-political approaches. It suggests that we may be getting closer to finding win–win solutions and overcoming the trade-off between biodiversity and food production. On the other hand, despite the growing body of literature directly addressing the nexus between biodiversity and food security, the overall volume of such publications remains limited. Key challenges persist, including the underdevelopment of research on political and economic dimensions, as well as a dearth of studies encompassing the entire food supply chain. The disparities in the number of studies and topics identified in this research serve as indicators of areas where further research is needed. In particular, the promotion of research in the political and economic domains is imperative for the development of a sustainable food system that integrates biodiversity conservation and food security.