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.     

Persistence of announcement effects on the intraday volatility of stock returns: Evidence from individual data

We analyze the persistence effects in the empirical relationship between announcement releases and return volatilities of four major companies of the French stock market using high frequency data over the period 1995–1999. Besides its institutional stability, this sample period avoids the econometric difficulties inherent to simultaneous news arrivals. Our approach contributes to the relevant literature in that we focus on individual stock volatilities rather than indices, we distinguish firm‐specific and macroeconomic announcements, and we endogenize both the durations of announcement effects and the response patterns of equity prices. We find that our individual volatilities are affected by a systematic market effect, calendar effects, announcements related to the firms’ macroeconomic environment and announcements related to the firms’ and their competitors’ strategic dealings and commercial outcomes. We find evidence that all volatility responses are gradual with persistence horizons ranging from one to three hours, revealing a significant degree of inefficiency of the French stock market over the period. This inefficiency can be viewed as a breeding ground for the implementation of more performant informational and trading systems that allowed markets to move towards more efficiency.     

Shrinking cities: urban challenges of globalization

Urban shrinkage is not a new phenomenon. It has been documented in a large literature analyzing the social and economic issues that have led to population flight, resulting, in the worse cases, in the eventual abandonment of blocks of housing and neighbourhoods. Analysis of urban shrinkage should take into account the new realization that this phenomenon is now global and multidimensional — but also little understood in all its manifestations. Thus, as the world's population increasingly becomes urban, orthodox views of urban decline need redefinition. The symposium includes articles from 10 urban analysts working on 30 cities around the globe. These analysts belong to the Shrinking Cities International Research Network (SCIRN), whose collaborative work aims to understand different types of city shrinkage and the role that different approaches, policies and strategies have played in the regeneration of these cities. In this way the symposium will inform both a rich diversity of analytical perspectives and country-based studies of the challenges faced by shrinking cities. It will also disseminate SCIRN's research results from the last 3 years.