The second edition of the ‘International Symposium on The Effects of Climate Change on the World’s Oceans’ will be held in Yeosu, Korea in May 15-19, 2012 under the sponsorship of the Intergovernmental Oceanographic Commission (IOC) of UNESCO, the International Council for the Exploration of the Sea (ICES), and the North Pacific Marine Science Organization (PICES). The Symposium is a main event programmed in the first week of the Expo 2012; it aims to attract more than 500 of leading scientists from different disciplines to present and exchange observations, results, models and ideas at a global scale and to discuss options to mitigate and protect the marine environment and its living resources. The symposium is organized in 10 different thematic sessions including climate variability, observations, projections, impacts, mitigation, etc. and has gathered the support of 14 leading organizations and research programmes in oceanography and/or climate change.