The natural asset base of the poorest, resource-dependent economies is being rapidly run down. Yet these economies remain in a fundamental state of 'underdevelopment.' In short, development is essentially 'unsustainable' because net depreciation of the natural asset base (and any increase in population) is not being compensated by investment in renewable (human and physical) capital. Clearly, a higher priority should be placed on efficient and sustainable management for natural resources to maintain the environmental 'capital' required for this transition and to achieve long term development goals. Rethinking the economic relationship between poverty and environmental degradation in developing countries from an economic perspective is also a necessary component of this new development thinking.