On Borrowed Time is a both comprehensive and concise study of the economics of mined resources and their related commodities. It is the perfect resource for anyone interested in investing or working in these commodities or their related industries or getting a better handle on how to interpret physical and economic measures of resource availability.
There are also significant applications for ecology and conservation efforts, which are addressed throughout the book. The included figures are very supportive and accompanied by explanations that make them easy to interpret. Tilton combines history, economics, and industry expertise to approach resource scarcity from every angle, but explains in a way that prior expertise in these areas is not necessary for the reader to comprehend.
The thesis is that enough minerals exist to sustain human usage for potentially millions of years; scarcity at any given moment is the result of the limitations of current technology and capital. As technology improves, it usually allows for extraction at monetary and environmental costs that society is willing to accept. If it ever reaches a point where it is possible, but no longer worth the costs, then society replaces the mineral with something else. We currently see natural gas, wind, and solar energy replacing coal for this reason. We are not running out of coal, it’s just not worth digging up as much as we used to. This is thanks to increased awareness of coal’s environmental costs, government subsidization of renewable energy investment, new technologies like fracking and more efficient wind and power generation, and natural market forces. All of these factors can work together to keep mineral allocation sustainable.