The IPAT-model developed by Ehrlich and Holdren is widespread in ecological economics in order to quantify the impact of population growth on environmental deterioration. We comment on this model and extensions proposed by several authors from a theoretical and empirical point of view.

This paper asks whether population growth is conducive to the sustainability of cooperation. A simple model is developed in which farmers who live around a circular lake engage in trade with their adjacent neighbors. The payoffs from this activity are governed by a prisoner's dilemma rule of...

The paper develops a model with non-exponential population growth, nonrenewable natural resources, and endogenous knowledge creation to analyse substitution between primary inputs and an essential use of resources in the innovation sectors, which is generally considered as most unfavourable for...