A variety of measures and concepts are evolving, each bringing a unique perspective to some aspect of monitoring sustainable scale:
- Carrying Capacity Biological science describes the parameters that determine the rise and collapse of living populations.
- The IPAT Equation Ecological Impact equals Population times Affluence times Technology; linking various human activities with ecologcial sustainability.
- Limits to Growth A variety of future scenarios project an unsustainable future (accurately to date) unless we change our ways.
- Ecological Footprint The Ecological Footprint is a standardized way to measure what has been immeasurable, contentious, and often misunderstood: ecological limits. It does this by comparing human resource demand to nature's ability to renew.
- Critical Natural Capital Some ecosystem services are more critical than others - they are necessary for our survival, cannot be replaced, and once lost are gone forever.
- Material Flow Analysis This methodology focuses on the sheer volume and types of material throughput that characterize various national economies; it highlights where the flows originate and where they end as wastes.
- Millennium Ecosystem Assessment This latest and most comprehensive scientific review of global ecosystems clearly documents that nature's services may not be there for us much longer.
- Panarchy This comprehensive conceptual framework connects different scale levels, and describes dynamic adaptive cycles through which ecosystems naturally evolve. It has proven a useful framework for many practical applications at the local and regional levels, and is now being examined at the global level.
- The Natural Step TNS focuses on an action plan for organizations to follow to achieve sustainability; its basic principles parallel those a sustainable scale perpsective.
- Ecological Economics Perspectives Sustainable scale is about how economic throughput impacts the ecosystems which contain and sustain the economy. It can be viewed in terms of stocks or flows, and both approaches add to our understanding.
- Selected Readings Additional Information on Measuring Scale.