The Environmental Kuznets Curve in the 21st century: Future projections under socioeconomic and climate change scenarios

This paper examines how economic development may impact future air pollution under alternative socioeconomic and climate change scenarios within the Environmental Kuznets Curve (EKC) framework. Leveraging scenario-based projections for seven air pollutants and gross domestic product per capita for 193 countries over the period 1980–2100, the analysis integrates Shared Socioeconomic Pathways (SSPs) and Representative Concentration Pathways (RCPs) into a forward-looking EKC assessment. The results challenge the universality of the classical inverted-U EKC, showing that declining income-pollution relationships emerge primarily under sustainability-oriented scenarios. The findings indicate that future improvements in environmental quality do not depend on economic growth alone, but on early policy intervention, energy system transformation, and agricultural modernization, underscoring the need for pollutant-specific and scenario-aware strategies to support cleaner production and long-term sustainability. • Economic growth alone does not ensure future improvements in air quality. • Income-pollution paths depend on development pathways and policy assumptions. • Emission declines emerge mainly under sustainability-oriented futures. • Early policy intervention is critical to achieve cleaner production outcomes. • Sulfur dioxide shows the most consistent decline across future scenarios.