This background paper, produced by IUCN in collaboration with ONERC, follows the proceedings of the IUCN conference "The European Union and its Overseas Entities: Strategies to Counter Climate Change and Biodiversity Loss", which took place on Reunion Island from 7 to 11 July 2008. The paper offers for the first time a comparative analysis of the 28 overseas entities of the European Union. It starts with a thematic analysis presenting the transversal threats on overseas entities in the face of climate change. Subsequent sections, specific for each of the 28 entities, provide some contextual data and an overview of their remarkable biodiversity, in addition to presenting the new threats resulting from climate change. Lastly, examples of responses to climate change or “best practices” are reported for selected territories.