| Popis: |
The objective of this paper is to provide a conceptual and empirical historic analysis of applications, misunderstandings, and fallacies surrounding the Hubbert curve, the U-shaped production curve of a commodity, and peak minerals. We show that the ultimate recoverable resources (URR) cannot be predicted by fitting a symmetric curve to the data of past (historic) production for any commodity on a global scale. Without knowledge of the URR, it is not possible to determine the peak production time. For well-confined areas, in the case of a supply market, it might be possible today to construct a satisfactory Hubbert curve and to determine peak production. For phosphate, the case of Nauru Island is a good example, but so far, it is not possible for any commodity worldwide. URR comprise past production, presently known reserves, and future reserves developed from resources (known, but uneconomic at present) and parts of the geopotential (not yet known, but by geological reasoning and technological innovations, reserves can be expected to be discovered). The concept of reserves is a dynamic one, determined by economic conditions, technological developments, etc. The reserves of today can be the resources of tomorrow and vice versa. These factors also influence production curves. Therefore, it is not justified to interpret every peak as caused by geological constraints. In most cases so far, peak curves are demand driven and not at all influenced by geological availability. In only a very few cases (like the curve for the lower 48 states of the USA for oil by Hubbert in 1956 or gold production in South Africa), they are supply driven, i.e., true Hubbert curves. Gold showed four peaks in the twentieth century. Since gold mining is ""money mining,"" there is always a demand for gold. Therefore, the causes for the peak development must be economic ones with no influence of physical-production demand factors, purely supply factors-a model case to study. We also show how the kind of commodity, government regulations, technologies, and commodity prices influence U-shaped production curves. For phosphate, we show that a peak cannot be predicted with the present base of knowledge. We face a reserve-to-consumption ratio of higher than 300, which is higher than for every major commodity and at least 10 times the length of innovation cycles in the mineral industry. If we take the dynamic nature of reserves into account, we doubt that it is very meaningful to discuss the reliability of reserve and resource data. Instead, under the aspect of long-term future supply and a postulated right to know based on the universal right to feed oneself in dignity, the geopotential of phosphorus as the source of future reserves and resources should be regularly examined by an international scientific body. |
