The impact of personal beliefs on climate change: the “battle of perspectives” revisited

The paper proposes a multi-agent climate-economic model, the “battle of perspectives 2.0”. It is an updated and improved version of the original “battle of perspectives” model, described in Janssen (1996) and Janssen/de Vries (1998). The model integrates agents with differing beliefs about economic growth and the sensitivity of the climate system and places them in environments corresponding or non-corresponding to their beliefs. In a second step, different agent types are ruling the world conjointly. Using a learning procedure based on some operators known from Genetic Algorithms, the model shows how they adapt wrong beliefs over time. It is thus an evolutionary model of climate protection decisions. The paper argues that such models may help in analyzing why cost-minimizing protection paths, derived from integrated assessment models à la Nordhaus/Sztorc (2013), are not followed. Although this view is supported by numerous authors, few such models exist. With the “battle of perspectives 2.0” the paper offers a contribution to their development. Compared to the former version, more agent types are considered and more aspects have been endogenized.