Revisiting the Environmental Kuznets Curve (EKC) Hypothesis: Empirical Evidence from Selected Sub-Saharan African Economies in the Context of Sustainable Development

Abstract

This study revisits the Environmental Kuznets Curve (EKC) hypothesis within the context of sustainable development in Sub-Saharan Africa (SSA), focusing on the relationship between economic growth, financial development, and environmental degradation. Drawing on panel data from seven purposively selected SSA countries—Côte d'Ivoire, Ghana, Kenya, Mauritius, Namibia, Nigeria, and South Africa—spanning the period 1993 to 2021, the study employs the Autoregressive Distributed Lag (ARDL) approach using Pooled Mean Group (PMG) estimation to capture both short-run and long-run dynamics. Environmental degradation is measured through three proxies: carbon dioxide (CO₂) emissions per capita, ecological footprint per capita (EFPC), and the ecological footprint index (EFPI). Control variables include energy consumption, foreign direct investment (FDI), urbanisation, and secondary school enrolment. Panel unit root and Pedroni cointegration tests confirm the presence of long-term relationships, while Granger causality tests explore the direction of causality between GDP per capita and environmental indicators. The findings support a cubic (N-shaped) EKC relationship across all three measures of environmental degradation, indicating that environmental quality initially worsens with rising income, improves after a threshold, but may deteriorate again at higher income levels. Additionally, energy consumption significantly contributes to CO₂ emissions and EFPC, while FDI and urbanisation exert mixed effects depending on the environmental metric. The error correction models show significant adjustment toward long-run equilibrium for CO₂ and EFPC, but not for EFPI, underscoring the persistent nature of broader ecological stress. Based on these findings, the study recommends region-specific policies that prioritize renewable energy investment, green urban infrastructure, and sustainable FDI flows, along with human capital development through expanded access to quality education, to ensure environmentally sustainable growth in SSA.