This lecture explores the concepts of efficiency and decoupling in environmental impact assessment. It discusses the necessity of absolute decoupling for certain environmental issues, the implications of the Environmental Kuznets Curve, and the challenges of achieving sustainable growth. The instructor presents evidence on the relationship between economic development and environmental performance, highlighting the complexities of reducing environmental impacts while promoting economic growth. Lessons learned include the importance of improving resource efficiency and the limitations of relying solely on market forces for environmental protection.