Sea ice, which covers about 10% of the world’s oceans, plays a major role in the Earth’s thermal balance and generates the driving forces of atmospheric and oceanic general circulation. The Sea of Okhotsk is the world’s lowest-latitude sea to freeze and marks the southernmost limit of drift ice. Every winter, 60–70% of the Sea of Okhotsk becomes covered with drift ice, bringing both benefits and challenges to our daily lives. In recent years, the impacts of global warming have led to a rapid decline in Arctic sea ice extent, causing a variety of environmental problems. At the same time, the “Arctic Sea Route” linking the Pacific Ocean and Europe has attracted increasing attention, though the international situation surrounding it remains delicate.
　　　Sea ice and drift ice are deeply connected not only to the global environment but also to productive activities such as fisheries, agriculture, and industry. This symposium addresses a wide range of topics, from the latest sea ice research to global warming, environmental issues, marine organisms, the Northern Sea Route, polar regions, and various issues concerning the Okhotsk region.
The International Symposium on the Okhotsk Sea & Polar Oceans has been held annually in Mombetsu City since its first meeting in 1986. Although the symposium was canceled in 2021 due to the spread of COVID-19, the academic sessions were held online in 2022 and in a hybrid format in 2023. From 2024 onward, the academic sessions have returned to an in-person format, and public lectures, the Children’s Drift Ice Symposium, and the commemorative reception have been resumed.
　　　This year’s International Symposium on the Okhotsk Sea & Polar Oceans in 2026 marks the milestone 40th meeting, at which many research presentations will be given on a variety of themes. We hope that the symposium will provide a fruitful forum for all participants to engage in meaningful discussions and deepen exchanges. We sincerely hope you enjoy the symposium.