East Asian countries have been facing a variety of common risks with regard to environmental, economic, and social sustainability such as human health problems caused by air, water, and soil pollution; the frequent occurrence of natural disasters because of earthquakes and climate change; nuclear power plant accident risks; and the increasing vulnerability of local communities due to depopulation and aging, all of which threaten human security, including life, subsistence, and dignity. This research project examines approaches to addressing complicated sustainability challenges in East Asia from various perspectives, including actors, the role of science, multilateral cooperation, governance, and case studies on energy transition in the region. Tackling these challenges has resulted in observable relevant public policy developments in each country; including bi- and multilateral intergovernmental cooperation and transnational cooperation between nonstate actors, such as NGO/NPOs and research groups. However, concerning national security issues in this region, non-negligible obstacles are present. Besides this, environmental sustainability issues have complex causal relations that require cross sectoral approaches. One policy suggestion in response to these complex environmental sustainability issues in East Asia is the pursuit of cooperative governance beyond geographical instability and uncertainty, as well as functional specialized approaches. This research bulletin collects abstracts of individual studies by members and summarizes their major findings.