Two centuries of carbon emissions (1800-2022): The role of government spending, economic growth, and population density in the United States.

Over the past two centuries, since the onset of the Industrial Revolution, human activities have exerted an unparalleled influence on the environment, with CO₂ emissions posing a major challenge to ecological sustainability. In this context, the United States (U.S.) stands out as a prominent historical emitter, providing a unique perspective for examining the underlying triggers of environmental degradation. This study analyzes in-depth the effects of government spending, economic growth, and population density on CO₂ emissions based on two centuries of data (1800-2022). The research seeks to build an empirical foundation for U.S. sustainable development strategies by assessing the link between these macro-level determinants and carbon intensity through the lens of the Environmental Kuznets Curve (EKC). The method of the study is based on the principles of econometric robustness and methodological reliability, utilizing the long period of the data set as well as four different long-term estimation techniques, including Augmented ARDL, FMOLS, DOLS, and CCR. The study confirms the EKC hypothesis for the U.S., spanning more than two centuries of data. It is suggested that government spending, when strategically allocated, can have emissions-reducing effects. On the other hand, it has been determined that population density has a structural and permanent effect that increases CO₂ emissions. In these aspects, the study provides an original framework that can contribute to both historical continuity and policy making in the environmental economics literature.