Sustainability measurement
Hubbert peaks
### Hubbert peaks

[thumb\|350x350px\|Hubbert Peak vs Oil Production](/wiki/File:Hubbert_peak_oil_plot.svg "Hubbert peak oil plot.svg")
There is an active debate about most suitable sustainability indicator's use and by adopting a thermodynamic approach through the concept of "[exergy](/wiki/Exergy "Exergy")" and Hubbert peaks, it is possible to incorporate all into a single measure of [resource depletion](/wiki/Resource_depletion "Resource depletion").The exergy analysis of minerals could constitute a universal and transparent tool for the management of the earth's physical stock.

[Hubbert peak](/wiki/Hubbert_peak_theory "Hubbert peak theory") can be used as a metric for sustainability and depletion of non\-renewable resources. It can be used as reference for many metrics for non\-renewable resources such as:

1. Stagnating supplies
2. Rising prices
3. Individual country peaks
4. Decreasing discoveries
5. Finding and development costs
6. Spare capacity
7. Export capabilities of producing countries
8. System inertia and timing
9. Reserves\-to\-production ratio
10. Past history of depletion and optimism

Although [Hubbert peak theory](/wiki/Hubbert_peak_theory "Hubbert peak theory") receives most attention in relation to [peak oil production](/wiki/Peak_oil "Peak oil"), it has also been applied to other natural resources.


What are some signs that a non-renewable resource may be approaching its Hubbert peak?