DIVA: An Iterative Method for Building Modular Integrated Models

Integrated modelling of global environmental change impacts faces the challenge that knowledgefrom the domains of Natural and Social Science must be integrated. This is complicated by often incompatibleterminology and the fact that the interactions between subsystems are usually not fully understood at the startof the project. While a modular modelling approach is necessary to address these challenges, it is not sufficient.The remaining question is how the modelled system shall be cut down into modules. While no generic answercan be given to this question, communication tools can be provided to support the process of modularisationand integration. Along those lines of thought a method for building modular integrated models was developedwithin the EU project DINAS-COAST and applied to construct a first model, which assesses the vulnerabilityof the world’s coasts to climate change and sea-level-rise. The method focuses on the development of acommon language and provides domain experts with an intuitive interface to code their knowledge in form ofmodules. However, instead of rigorously defining interfaces between the subsystems at the project’s beginning,an iterative model development process is defined and tools to facilitate communication and collaboration areprovided. This flexible approach has the advantage that increased understanding about subsystem interactions,gained during the project’s lifetime, can immediately be reflected in the model.