In 1900, approximately 80% of the elements humans used came from biomass (wood, plants, food, etc.). That figure had fallen to 32% by 2005, and is expected to stand at approximately 22% in 2050. We are heading for a situation in which 80% of the elements we use are from non-biological sources.
Non-biological elements are scarce or practically absent in living organisms, and rare in general; in many cases, their main reserves are located in just a handful of countries. They must be obtained from geological sources, which entails extraction, trade between countries, and the development of efficient recycling technologies, while their scarcity and location create potential for social, economic, geopolitical and environmental conflicts.