Final Report Summary - COMPASS (Comparative Assessment of Coastal Vulnerability to Sea-Level Rise at Continental Scale) There is currently increasing concern among scientists and policy makers regarding the potential impacts of sea-level rise in coastal regions. Although these impacts are expected to be significant, their magnitude is uncertain due to, among others, the lack of sufficient knowledge regarding the actual amount and rates of rise; but also due to uncertainties regarding the response of coastal societies and systems to rising sea levels.It is therefore important for decision makers to be informed on the potential costs and benefits of adaptation as well as on the costs of inaction, in order to develop sustainable adaptation strategies. However, there is generally a lack of adequate tools designed to provide policy makers with estimates of potential future impacts of sea-level rise under a range of scenarios and adaptation strategies. This lack is more pronounced in developing countries, where such tools are seldom available, and even when they exist, their use is often limited by issues such as incomplete data, computing power or the scale of application.The aim of COMPASS has been the transfer of knowledge on the development and application of such a tool, namely the Dynamic and Interactive Vulnerability Assessment (DIVA) model,; while at the same time expanding the knowledge base of the model with local data and experience on relevant processes from regional experts. In this context, the project has undertaken a number of work packages to accomplish the following key objectives:1. To provide a complete overview of the DIVA tool and its elements (database, models, GUI) to the South American partners.2. To apply DIVA at continental scale and conduct analyses for Europe and South America, aiming to quantitatively assess the impacts of sea-level rise in the two continents 3. To evaluate and validate the outputs from the application of DIVA for South America, using local expert knowledge and data collected during studies conducted in the region; and to understand the institutional framework in which DIVA results could be used to support policy makers.4. To explore the potential for the further development of DIVA, by addressing limitations related to data and algorithmsCOMPASS has provided an extensive training programme on the development of the elements of the DIVA integrated assessment tool to all South American institutions involved in the project.In a series of training sessions, lead by researchers from the European institutions, which took place in Argentina, Brazil and Chile, the basic principles for the development of the database and models were presented and hands-on training on the DIVA tool was provided to audiences of academics and students. Further training took place in the European institutions (in Germany and Greece) for seconded researchers.Applications of DIVA for Europe and South America were then carried out and updated assessments of impacts and costs of sea-level rise were produced for the two continents. Results indicate high damage costs and show that large numbers of people flooded are expected for South American countries, with poorer countries being affected most. Adaptation was found to reduce these impacts, however substantial investment in adaptation measures will be required. Moreover, high salinity intrusion and loss of wetlands will be more difficult to deal with due to the lack of effective adaptation methods. Europe will also face high damage and adaptation costs. However, adaptation appears to be highly beneficial in reducing impacts and is also expected to be affordable in terms of proportion of the annual GDP. The evaluation of the outputs with experts from all institutions has helped to evaluate potential limitations in the results and to identify areas for further development. Following this work, an updated version of the DIVA database was produced for South America and work on further development of DIVA algorithms was initiatedFinally, in the context of the above work, new objectives were established during the course of the project. These include a review of previous assessment of coastal vulnerability to sea-level rise that have been conducted in South America and an analysis of the implementation of coastal adaptation in Argentina. Although this work is still underway, preliminary results indicate the lack of consistent and comparable vulnerability analyses to sea-level rise in the region and, in the case of Argentina, the implementation of a wide range of hard adaptation measures but also very complex and, in many cases, not clearly defined institutional structures for the planning of those measures.We anticipate that the knowledge transferred during COMPASS will assist in the development of tools to address the above limitations and to provide support for policy making regarding long-term sea-level rise and associated impacts. Lastly but equally important, the work carried out in COMPASS has led to the development of strong links and a solid basis for long-term collaboration between the participating European and South American institutions. This is already demonstrated in a series of new co-operations, in the form of research projects and research visits, funded by the national research organisations of the participating countries.