“…Indeed, the main emphasis in theoretical works has traditionally been placed on the extra stress generated by population growth on the limited availability of land and natural resources (see, among others, Solow, ; Cigno, ; Nerlove, ; Dasgupta, ; Peretto and Valente, ), while most of the empirical works have focused on the impacts of population changes on environmental quality or pollution (Kaya, ; Rosa and Dietz, ). An important conclusion of such an empirical literature is related to the fact that environmental deterioration depends not only on economic activities (eventually net of green technological progress) but also on human population; however, among the few theoretical works that relate population growth to environmental quality (Harford, ; Schou, ; Jöst and Quaas, ), none addresses the specific role of population as a separate (from economic activities) driver of pollutant emissions, as suggested by the empirical evidence on the IPAT equation (Rosa and Dietz, ). We thus contribute also to this limited branch of the literature by developing a more comprehensive approach to the role of population growth as a source of environmental degradation per se.…”