A framework for the practical application of the concepts of critical natural capital and strong sustainability

This paper develops a methodology for identifying that natural capital—called critical natural capital (CNC)—the maintenance of which is essential for environmental sustainability. By consideration of the characteristics of natural capital, of the environmental functions that these characteristics enable natural capital to perform and of the importance of these functions to humans and the biosphere, it shows how sustainability standards in respect of these environmental functions may be derived. The difference between the current situation and these standards is termed the sustainability gap. The methodology that emerges from bringing these ideas together into a single analytical framework enables policy makers to identify the extent of current unsustainability, the principal causes of it, the elements and processes of natural capital (the CNC) which need to be maintained or restored to close the sustainability gap and the costs of so doing. The framework should therefore be of use in identifying priorities and policies for moving towards environmental sustainability.