Alterations in the ocean and polar and mountain cryosphere from climate change have the potential for far-reaching impacts on ecosystems and human systems all over the world. The IPCC Special Report on Ocean and Cryosphere in a Changing Climate (SROCC) was prepared in response to proposals of member governments and observer organisations for Special Reports assessing highly policy-relevant issues. This report focuses on observed and projected changes in the ocean and cryosphere; impacts, vulnerability and risks to ecosystems and human systems, as well as adaptation options. The SROCC is structured in six chapters: Framing and context of the report; high mountain areas; polar regions; sea level rise and implications for low lying islands, coasts and communities; changing ocean, marine ecosystems, and dependent communities; extremes, abrupt changes and managing risks; together with an integrative cross-chapter box on low-lying islands and coasts. Over 100 scientists from 36 countries led the assessment of the latest scientific knowledge in more than two years of intense work. This presentation will provide some background information, an overview on the milestones during report development and focus on the key messages from the report’s Summary for Policymakers.