Sustainable Consumption or Ecological Outsourcing? Quantile Evidence on Marine Environmental Quality in BRICS Economies

Marine environmental sustainability is increasingly challenged by rising ecological pressure, trade integration, and environmentally intensive growth dynamics, particularly in emerging economies. This study investigates the nonlinear determinants of marine environmental quality by examining the effects of ecological footprint, greenhouse gas emissions embodied in imports, trade openness, governance quality, and economic growth across four BRICS economies, Brazil, China, India, and South Africa, over the period 2012–2025. To capture heterogeneous and asymmetric relationships, the analysis employs Quantile Regression (QR) and Quantile‐on‐Quantile Regression (QQR). The findings reveal substantial distributional heterogeneity across quantiles and countries. Ecological footprint generally shows a negative effect on marine environmental quality, with stronger adverse impacts observed in environmentally vulnerable regimes. Similarly, trade‐embedded greenhouse gas emissions significantly deteriorate marine environmental quality, although the magnitude and direction of these effects vary across countries and quantiles. Trade openness presents highly nonlinear and regime‐dependent effects, while governance quality improves marine environmental quality, particularly within stronger institutional regimes. Economic growth shows asymmetric effects across the conditional distribution. The QR estimates confirm the robustness of the QQR results, while the country‐specific analysis reveals substantial cross‐country heterogeneity. These findings highlight the importance of strengthening environmental governance, promoting sustainable trade practices, and reducing ecological outsourcing to support progress toward SDGs 12, 13, 14, 16, and 17.