A tripartite evolutionary game analysis of Japan's nuclear wastewater discharge

Abstract

Japan's decision to discharge nuclear wastewater into the sea on April 13, 2021 has aroused worldwide discussions recently. This paper establishes a tripartite evolutionary game model to explore the evolutionary stable strategies (ESSs) of Japan, other countries, and international environmental protection organization (IEPO). The results show: i) The choice of Japan is closely related to the treatment cost of nuclear wastewater. When Japan chooses the non-discharge strategy, other countries will always choose the acceptance strategy, while IEPO will trade off between its credibility and international assistance. When Japan chooses the discharge strategy, the choice of other countries depends on the difference of litigation compensation and cost, while that of IEPO is determined by the comparison of the litigation compensation and credibility with the litigation cost. ii) The treatment cost of nuclear wastewater, negative externalities of marine environment, litigation compensation, international assistance from IEPO, and the proximity coefficient between Japan and other countries are critical factors influencing both evolutionary results and trajectories, while the international assistance from other countries and initial willingness only affect evolutionary trajectories. This paper also puts forward policy implications for the three stakeholders to promote Japan's non-discharge strategy so as to protect the marine environment and human health from the unprecedented damage.