Evolutionary Climate-Change Modelling: A Multi-Agent Climate-Economic Model

In climate-economic modelling, agent-based models are still an exception. Although numerous authors have discussed the usefulness of the approach, only a few models exist. The paper proposes an update to a multi-agent climate-economic model, namely the “battle of perspectives” (Janssen, 1996; Janssen and de Vries 1998). The approach of the paper is twofold. First, the reimplementation of the model follows the “model to model” concept. Supporters of the approach argue that replication is a useful way to check a model’s accuracy and robustness. Second, updating a model with current data and new scientific evidence is a robustness check in itself. The long-term validity and usefulness of a model depends on the variability of the data on which it is based, as well as on the model’s sensitivity to data changes. By offering this update, the paper contributes to the development of agent-based models in climate-economics. Acknowledging evolutionary processes in climate-policy represents a useful complement to intertemporal cost-benefit analyses, the latter of which derive optimal protection paths but are not able to explain why people do not follow them. Since the replication and update succeeded, the paper recommends using the model as a basis for further analysis.