As the global population heads toward 9 billion by 2050, decisions made today will lock countries into growth patterns that may or may not be sustainable in the future. Care must be taken to ensure that cities and roads, factories and farms are designed, managed, and regulated as efficiently as possible to wisely use natural resources while supporting the robust growth developing countries still need. Economic development during the next two decades cannot mirror the previous two: poverty reduction remains urgent but growth and equity can be pursued without relying on policies and practices that foul the air, water, and land. Inclusive Green Growth: The Pathway to Sustainable Development makes the case that greening growth is necessary, efficient, and affordable. Yet spurring growth without ensuring equity will thwart efforts to reduce poverty and improve access to health, education, and infrastructure services. Countries must make strategic investments and farsighted policy changes that acknowledge natural resource constraints and enable the world's poorest and most vulnerable to benefit from efficient, clean, and resilient growth. Like other forms of capital, natural assets are limited and require accounting, investment, and maintenance in order to be properly harnessed and deployed. By maximizing co-benefits and avoiding lock-in, by promoting smarter decisions in industry and society, and by developing innovative financing tools for green investment, we can afford to do the things we must.