The natural resources sector in the structure of the world economy and the causes of the global economic crisis

摘要

Humans withdraw the materials they need from natural systems and, applying technologies, where necessary, process and transform those materials, i.e., decompose, combine, synthesize new materials, thus arriving at products to be used in final consumption or as instruments of labor in production. By tracing the path of such transformations from the original natural material to the final product, we obtain the production or process chain. In fact, what is commonly referred to as the process chain, is not a chain from the mathe matical or graphtheoretical viewpoint (Fig. 1a); it is a much more complex graph (e.g., such as that in Fig. 1b), because even in high antiquity (and certainly after the invention of metallurgy), to obtain many final products at different stages of their production, one needed various original natural (raw-material) components and their transformation products. For this reason, the word "chain" should be used with quotation marks or, better, replaced by another term, i.e., process graph.