Climate change poses various risks to nature and society on a global scale. Nations have agreed to keep the increase in the global mean temperature well below 2 degrees Celsius by achieving net-zero greenhouse gas (GHG) emissions. While achieving net-zero GHG emissions is inevitable to minimize the risks caused by climate change, it is not the only way to reduce the risks, and it does not cancel all of the risks related to climate change. Moreover, attempts to reduce GHG emissions can also pose non-negligible risks. Considering its spatially and temporally broad impacts on multiple domains, integrated assessments of the risks, including value judgement, is necessary when we tackle the issues related to climate change.

This paper presents “solution-focused risk assessment (SFRA)” as a useful approach for policy making. The purpose of risk assessment is not just to alert, but rather to support the decision as to which risk management measures should be taken. SFRA is to show several risk management measures and evaluate their risk mitigation impact, costs, risk trade-offs, and so on. Recent examples of SFRA were shown, including measures against COVID-19 and maritime safety. In addition, the factors may limit the implementation of SFRA were discussed. One of the factors is that the governmental sides don’t prefer the SFRA. Because they can transfer the responsibility to the experts for the explanation and results of the decision by explaining that “the decision was made by experts’ opinions” or “the decision was made based on science”.

Risk analysis approaches involving risk assessment, management, and communication have been developed independently in radiological protection, food safety, and environmental sciences. Summarizing the commonalities and differences in risk analysis methodologies in these fields may contribute to updating future risk analysis. Therefore, this review summarizes the multifaceted perspectives of risk assessment, management, and communication, with actual application examples, by introducing the birth of risk concepts and various risk indicators, and the historical development of risk management and assessment. Particularly, reviewing the relationship of socio-psychological aspects, the importance of ethical and normative perspectives, and the role of dialog with stakeholders is helpful. Based on these reviews, we note that understanding and applying risk indicators across fields is necessary in comparing different types of risk events. Furthermore, we mention that the application of risk assessment that considers egalitarianism and maximin principles will become more important in the future when emphasizing the consideration of ethical and normative perspectives in accordance with the social context and needs from the field. We then discuss the challenges and the need to update the risk analysis for planning and crisis management. We argue that incorporating collaboration with stakeholders can lead to ethically and socially acceptable risk assessment, management and communication.

In order to reduce carbon dioxide emissions and use hydrogen on a large scale, it is essential to promote the use of hydrogen and convert it into a suitable form for storage and transportation, called energy carrier. Among them, ammonia, which is made by synthesizing hydrogen and nitrogen, is one of the most promising substances. In Japan, on the other hand, excess sludge generated in sewage treatment plants is attracting attention as feedstock for hydrogen production. However, few case studies have evaluated the risks of ammonia release from synthesizing ammonia from hydrogen made in sewage treatment plants. Therefore, we aimed to evaluate the impact of chemical spills from this process and identify the vulnerable part in the components where risk countermeasures are needed. In conclusion, it is crucial to take measures such as increasing the strength of compressors and joints and executing daily inspections.

It is important for the decision making against COVID-19 to understand characteristics of vaccine hesitancy and acceptance. Many studies have shown that COVID-19 vaccine hesitancy was correlated with demographic characteristics such as age, gender, and incomes, but there has not been sufficient evidence whether COVID-19 fatigue affected public acceptance of vaccine. In addition, previous studies have discussed vaccine hesitancy without adequate consideration for the diversity of individual vaccination behaviors. Therefore, we conducted a questionnaire survey of university students to investigate factors causing vaccine hesitancy and acceptance and to examine individual differences. Answers of 191 respondents were collected. Perceived risk toward COVID-19 did not influence vaccine intention, while concerns about vaccine side effects and unreliability of vaccine efficacy contributed to hesitancy. Respondents who believed that they might be relieved of COVID-19 stress after vaccination tended to accept vaccine. Vaccine hesitant respondents were divided into subgroups by cluster analysis. Reasons for hesitancy vary greatly among subgroups. A factor of hesitancy for one group was not always a factor for another group.

In COVID-19, the use of science and technology is required to achieve a balance between infection control and the maintenance of socioeconomic activities. In doing so, people’s understanding and acceptance of science and technology are indispensable. Therefore, in this study, we took up three new technologies that contribute to COVID-19 countermeasures: contact confirmation application (COCOA), health observation application, and sewage surveillance, measured the cognitive and affective factors toward each technology and the attitude toward social acceptance, and examined the psychological factors that prescribe the acceptance attitude. The results showed that trust in performance, perceived benefits, perceived risks, and negative emotions toward the technology were significant determinants for all the technologies.

The purpose of this study is to examine the characteristics of perceived risk of recidivism in the general public in comparison with actual crime statistics. Participants were 280 female university students, and they were asked to estimate risks of reincarceration of released prison inmates within five years using a web-based self-report questionnaire. Results showed that the risks of recidivism were overestimated for sex offenders and drug offenders while they were underestimated for those who committed theft, assault, and arson compared to the actual statistical data shown in the White Paper on Crime. Future research recommendation and practical implications, especially on recidivism risk communication, were discussed.

Ethanol-based hand sanitizing is an effective preventive measure in COVID-19 pandemic. More than 60 vol% ethanol is effective against SARS-CoV-2. On the other hand, commercial ethanol-based hand sanitizers, commonly used in society, often contain not only ethanol but also various additives. As it is reported that some additives affect the disinfectant effect of ethanol, the effects of each formulation need to be evaluated for reducing the risk of infection in society. In this report, we demonstrate five commercial ethanol-based hand sanitizers are effective against multiple microorganisms including SARS-CoV-2.

Majority of attendees of the Society for Risk Analysis Japan (SRAJ) annual meeting seems to academic researchers or researchers of governmental institute. On the other hand, researchers of private company seem to be rather minority. Many factors may have been influencing on the decision making of participation to the annual meeting, we may have any firm analysis on these factors so far. As a preliminary study, we investigated two subjects: a) interest in research paper of SRAJ, and b) possible determinant of participation to the annual meeting by using e-mail questionnaire and/or interview to selected subpopulation of private company.

Date City in Fukushima prefecture has manually measured ambient dose equivalent rates after the Fukushima Nuclear Power Plant accident on March 11, 2011. The purpose of this study is to estimate long-time radiation doses by measuring ambient dose equivalent rates. In order to estimate the dose equivalent rates, mathematical models were used. The model consists of fast and slow weathering components (two-component), and radioactive decays of ¹³⁴Cs and ¹³⁷Cs. And after the decontamination, the dose rate was calculated by a one-component model. As a result, the half-lives of component 1 and component 2 at the sites were 1.2×10^-2–7.5×10^-2 years and 1.2–3.1 years, respectively. The values of component 2 were about two orders of magnitude larger than those of component 1. Furthermore, the half-lives of the one-component model after decontamination were 2.7–7.2 years, which were bigger than those of the component 1. The extra radiation dose for 50 years was estimated as approximately 85 mSv at the site of the maximum initial ambient dose equivalent rate and less than 40 mSv at other 14 sites. More than 80% of the extra radiation doses were integrated within 10 years after the accident.

An effect of commercial hand sanitizers containing ethanol (EtOH) combined with benzalkonium chloride (BC) on inactivation of Influenza A virus (IAV) and SARS-CoV-2 was investigated under conditions of exposure time 15 sec, to supplement our previous article reporting the testing results of the inactivation under exposure for 30 sec. All the results tested showed more than 4log₁₀ reduction for IAV and SARS-CoV-2. The results demonstrated that, under conditions of the shorter exposure, close to the real rubbing usage, the commercial hand sanitizers containing low-concentrated EtOH (44–65 vol%) combined with 0.05w/v% BC are effective to inactivate IAV and SARS-CoV-2.