This document discusses living more sustainably. It defines key terms like economics, environment, environmentalism, natural capital, and sustainability. It then discusses paths to sustainability, noting that a sustainable society balances natural resources and services. It also discusses the relationships between population growth, economic growth, and economic development. Population growth has slowed but still increases the world's population by over 80 million people each year. Economic growth is measured by GDP, while economic development improves living standards through growth.