DIVA is an integrated, state-of the-art research modelling framework for coastal systems that assesses biophysical and socio-economic consequences of sea-level rise and socio-economic development. It takes into account coastal erosion (both direct and indirect), coastal flooding (including river mouths), wetland change and salinity intrusion into deltas and estuaries. Adaptation and associated cost is a crucial part of the model.
Spatially, DIVA works on a database of linear coastline-segments. A polygon of the global coastline is divided into segments of coast with a homogeneous socio-economic and bio-physical characteristics. To do so, the polygon is cut at all positions where one of the underlying raster layers (coastal morphology, tidal type, population density, etc.) or polygon layers (country, administrative unit) change. The global default database of DIVA contains 12,148 segments. This technology can be downscaled to a finer resolution. On regional or national level often more detailed versions of the digital coastline as well as of the underlying bio-physical or socio-economic layers are available. Thus, local versions of the DIVA database can be developed. Downscaling has been applied for several countries and regions (Croatia, Tunisia, China, Maldives, German Baltic Sea coast, Emilia Romagna coast).
The DIVA modelling framework can be used to access impacts of the following processes:
- Coastal flooding and permanent inundation
- Coastal Erosion
- Change in global wetland area
DIVA is co-developed amongst a number of European research institutions. Core development is done by:
- Global Climate Forum (Adaptation and social learning, Daniel Lincke and Jochen Hinkel): GCF coordinates the research and the development of the DIVA model. It integrates modules and data from the different partners and provides the tools-chain to perform analysis. Due to its social science experience GCF develops the social components of adaptation in the model. GCF also maintains the DIVA model code.
- University of Southampton (Coastal Engineering and Management, Robert J. Nicholls): University of Southampton contributes to the modelling of bio-physical coastal impacts (floodings, erosion) with a focus on deltas and estuaries. As a coastal engineering group they provide the technical and economic components of adaptation in the model.
- Kiel University (Coastal Risks and Sea-Level Rise Research Group, Athanasios Vafeidis): Kiel University provides most of the coastal input data used within DIVA. Their expertise in digital elevation data, digital population data and GIS systems is used to compile the coastal database based on the segmentation of the digital coastline, which is also provided by Kiel University.
Contributions to processes and modules of DIVA were provided by:
- Cambridge University Coastal Research Unit (Cambridge Coastal Research Unit, Tom Spencer): Cambridge University Coastal Research Unit developed the first version of the DIVA wetland module. Due to their empirical wetland research they were able to provide calibration data for the DIVA wetland module.
- University of Lincoln (Mark Schuerch): Mark Schuerch developed the new DIVA wetland module and contributed to the integration of the module in DIVA. He also modelled interactions between wetlands and coastal protection infrastructure as well as the possible use of wetlands in coastal protection (nature-based solutions).
- University of Sussex (Department of Economics, Richard S.J. Tol): Richard Tol contributed the socio-economic country-level database for DIVA and developed econometric models of adaptation to flooding (dikes) and to erosion (nourishment).
The first version of DIVA (Dynamic Interactive Vulnerability Assessment) was developed 2001-2004 by Jochen Hinkel and the consortium of the EU-project DINAS-COAST. The first version already contained flooding, erosion and wetland change as processes, but the data used was rather coarse. It was completely developed in JAVA.
In the following years DIVA was continuously developed and applied, for instance in the EU-projects CLIMATECOST and IMPAT2C DIVA was used to estimate the economic cost of sea-level rise. Results from DIVA also contributed to the inter-sectoral impact model intercomparison project (coastal sector).
A new version of DIVA was developed 2013-2016 within the RISES-AM project. The former JAVA-model was reimplemented as a modelling framework allowing for easy exchange of modules and databases. Thus, the new DIVA is no longer a model but rather a framework for different coastal models and their combinations. The new framework was programmed by Daniel Lincke in Scala taking advantage of a modern multi-paradigm (object-oriented, functional) language. The model got more concise and clear than the Java version without loosing compatibility with the Java virtual machine. Further, databases have been updated taking into account the most recent versions of digital elevation data, population data, storm surge data, beach erosion data and tidal data. The adaptation models for the DIVA processes have been further developed. While a simple protection model based on econometric data has been part of DIVA from the beginning new adaptation models include cost-benefit analysis for protection as well as construction restriction by the means of setback zones and managed realignment.
From 2018 onwards DIVA is used in the next generation, co-designed assessments of climate change costs in the COACCH project.