This special report does not seek to paint a comprehensive picture of the state of the oceans. It does not set out to recapitulate the many years of debate on ocean overfishing. WBGU concentrates instead on those key linkages between climate change and the oceans that are the topic of new scientific insights.These insights include new findings on warming, ocean currents, sea-level rise, carbon uptake and acidification, and on the impacts of these factors upon marine ecosystems.The report also discusses in detail the development of tropical cyclones, the issues surrounding carbon storage in the ocean or under the seabed, and the risks associated with methane hydrate deposits in the sea floor. Many of these issues are closely interlinked