A social science approach is needed in addition to a natural science approach when assessing the impact of climate change on a region and examining adaptation measures. A social science approach is needed in addition to a natural science approach for four reasons: (1) an overall elucidation of the impact including socioeconomic aspects, (2) an impact assessment from the perspective of the vulnerable, (3) an examination of structural adaptation measures, (4) to complement and strengthen the participation and learning of residents and businesses.

To show the effectiveness of a social science approach, this paper summarizes research findings using the social science approach, and reports on two studies. One is action research on adaptation measures for Ichida persimmon in Takamori Town, Nagano Prefecture. The other is a study on the impact of climate change on the fishing industry in the Hinase district of Bizen City, Okayama Prefecture.

These two studies include interviews and questionnaire surveys of climate change-affected producers to clarify the climate change impact structure that reflects the special circumstances of the region. In addition, the studies suggest the possibility of regional adaptation measures to be taken to improve the management structure of producers.

Artisanal and small-scale gold mining is the main source of anthropogenic mercury on the planet, and the personnel engaged in these activities are at risk of exposure to mercury vapor. We developed an inexpensive and simple device for measuring mercury concentrations in the air using a quartz crystal microbalance. This device can be used as an individual exposure monitor, but whether its signals reflect actual exposure concentrations was unclear. We therefore examined the efficacy of the device as an individual exposure monitor in rats. Using active dehumidification, we found that the frequency of the quartz crystal microbalance device and the amount of mercury adsorbed to the crystal unit correlated with total mercury concentrations in various organs. This study suggests that the passive method is not suitable for using QCM-Hg as an individual exposure monitor, but is suitable for the active method.

In Japan, the Act on Promotion of Food Loss and Waste Reduction was enacted in 2019, and the government set a goal to halve food loss and waste by 2030 compared to the 2000 level. However, there are few quantitative findings regarding the impacts of food loss and waste on the environment, economy and society, and the detailed information is necessary to effectively implement reduction measures. Therefore, this study estimated greenhouse gas emissions, land and water resource losses, and food economic value losses that occur due to the Japanese food loss and waste generated in the food manufacturing industry, wholesale industry, retail industry, food service industry and households, targeting 19 agriculture, forestry and fishery products and 29 processed foods. Consequently, the total Japanese food loss and waste was estimated at 6.46 million tonnes in 2015, and the total greenhouse gas emissions resulting from food loss and waste was estimated at 15.66 million tonnes of CO₂ eq. In addition, 1.11 million hectares of harvested land were used to produce food that was eventually wasted, and 439 million m³ of water resources was wasted. Furthermore, the economic value of lost food was estimated at 4,587 billion yen.

We investigated the effects of aging plastics on the photodegradation of 2,4,5-trichlorophenol (TriCP), using polyethylene (PE), polyethylene terephthalate (PET), and polyvinyl chloride (PVC) sheets. A comparison of the TriCP photodegradation constants on glass and plastic sheets indicated that photodegradation was accelerated on the virgin PE sheet, but suppressed on the PET and PVC sheets. The photodegradation rates of TriCP on aged PE, PET, and PVC were significantly lower than those on the corresponding virgin plastic samples and glass. The results confirmed that the aging of plastics affects the TriCP photodegradation of TriCP. Analyses of the aged plastic samples indicated valley formation. In addition, the transparency of the plastic sheets to UV was reduced, thereby indicating that a decrease in UV intensity may contribute to the suppressed photodegradation on the aged plastic sheets. Furthermore, the methanol extract of the plastic sheets suppressed the photodegradation of TriCP. These results confirm the need to consider aging effects when investigating the fate of organic pollutants adsorbed on plastics, due to changes in the textures and decreases in the transparency of plastics, and the potential leaching of additives into the environment.

In Japan, the proportion of low-income households is increasing and the poverty rate of children is also increasing. Food banks that collect food that is still edible and provide it to low-income households can contribute to solving the problems of both food waste and poverty, but it has been pointed out that the food provided is mainly dried foods and there is a shortage of vegetables. In this study, we considered the system to provide vegetables from citizens’ farms to low-income groups through food-support organizations such as food banks in the future. A questionnaire survey was conducted in December 2019 for food banks and children’s cafeterias throughout Japan with the aim of clarifying the possibility of cooperation with farms. Responses were received from 38 food bank groups and 94 children’s cafeterias.

Food-support groups received more vegetables from farmers than initially expected. The proportion of receiving vegetables was smaller in food banks than that of children’s cafeterias. Regarding cooperation with citizens’ farms, nearly 90％ of children’s cafeterias responded positively to cooperation, while food banks and groups that had no experiences to handle vegetables were reluctant to cooperate. In addition to the past experience of handling vegetables, concerns about the timing of provision and quality/type of food had a significant negative impact on the possibility of collaboration in food banks.