The article by Thomas Dietz and Eugene A. Rosa explores the environmental impacts of population, affluence, and technology, focusing on the IPAT model, which posits that environmental impact (I) is the product of population (P), affluence (A), and technology (T). The authors argue that while the IPAT model has been widely used, it lacks empirical testing and fails to disentangle the various driving forces of environmental change. They propose a stochastic reformulation of the model to make it more suitable for empirical testing and to better capture the complex interactions between population, affluence, and technology. The authors also highlight the need for a more comprehensive approach that integrates insights from both social and biological sciences. They emphasize the importance of considering the distribution, age structure, and pace of population growth, as well as the need for alternative measures of affluence and technology that go beyond traditional economic indicators. The article concludes by advocating for a human ecological model of environmental impact that accounts for the interactions between human activities and the environment, and that integrates diverse perspectives from various disciplines to better understand and address anthropogenic environmental change.The article by Thomas Dietz and Eugene A. Rosa explores the environmental impacts of population, affluence, and technology, focusing on the IPAT model, which posits that environmental impact (I) is the product of population (P), affluence (A), and technology (T). The authors argue that while the IPAT model has been widely used, it lacks empirical testing and fails to disentangle the various driving forces of environmental change. They propose a stochastic reformulation of the model to make it more suitable for empirical testing and to better capture the complex interactions between population, affluence, and technology. The authors also highlight the need for a more comprehensive approach that integrates insights from both social and biological sciences. They emphasize the importance of considering the distribution, age structure, and pace of population growth, as well as the need for alternative measures of affluence and technology that go beyond traditional economic indicators. The article concludes by advocating for a human ecological model of environmental impact that accounts for the interactions between human activities and the environment, and that integrates diverse perspectives from various disciplines to better understand and address anthropogenic environmental change.