Investigating the Relationship Between Income Inequality, Institutional Quality, Trade Openness, and Ecological Footprint in Nigeria: A Quantile-on-Quantile and Wavelet Quantile Correlation Analysis

Environmental pressure in Nigeria persistently escalates despite several development efforts, prompting questions about the structural factors contributing to the nation’s ecological vulnerability. Considering this, the study employs a time-series research design that synthesizes collective theoretical perspectives to elucidate the interplay between income inequality (GINI), institutional quality (INST), trade in services (TO), and population density (POPd) in shaping Nigeria’s ecological footprint (ECF), utilizing data for the aforementioned variables from 1960 to 2024. The analysis shows time-varying dynamics across pollution regimes using Quantile-on-Quantile Regression (QQR) and Wavelet Quantile Correlation (WQC). The result reveals notable asymmetries across the ECF distribution. GINI and POPd intensify ecological pressure mainly at higher ECF quantiles. While INST serves as a key mitigating factor of ECF, particularly in a long-term pollution scenario. TO exhibits a regime-dependent effect, aligning with the Pollution Haven expectation in poor environments. These findings suggest that environmental outcomes in emerging economies are shaped by structural inequality and institutional strength. Highlighting the necessity of building institutional capacity to decouple inequality that drives ecological degradation. Thus, connecting national strategies with the Sustainable Development Goals (SDGs) 1, 8, 10, 11, 12, 13, 15, 16, and 17. These provide actionable insights into an inclusive and resilient environment.