Overview

Phosphorus is a unique critical element. It is in the precarious situation of being both a limited, minable resource, and a nutrient essential to organic life. The average adult requires around one gram of phosphorus per day; to sustain one person for a year requires mining 22.5 kg of phosphate rock (Vaccari, 2009). Phosphate use in modern agriculture supported the green revolution's increased crop yields, enabling the human population to grow from 3 billion in 1960 to over 7 billion today (US Census Bureau). If the world's supply of usable phosphorus in the form of phosphate is depleted, sustaining life, human and otherwise, will become considerably more challenging: agriculture as we know it will end, and billions of people will likely starve. While it is currently mined in sufficient quantities to meet global demand, the continued growth of the population and consequently the increase in demand will lead to a critical supply shortage over the course of the coming century. Modifications to the way phosphorus is produced and consumed must be made immediately to avoid irreversible consequences.

Properties and Applications

Phosphorus is a versatile element, and it is used in a variety of applications worldwide: as a nutrient in fertilizer for agriculture, an ingredient in livestock food supplements, and a component of detergents, pesticides, nerve agents, and matches, among other common products [Florida Industrial and Phosphate Research Institute (FIPR), 2010]. However, phosphorus is biologically irreplaceable, and all told, nearly 90% of current phosphorus is used directly in the global food supply chain (The Fertilizer Institute). While cutting back use in other areas will help to lower total consumption somewhat, phosphorus must be most aggressively conserved and recycled in its agricultural applications.

Environmental Impact

In addition to depleting finite reserves, overuse of phosphate fertilizers presents an environmental problem. When applied haphazardly or in excess, phosphorus from farms can be washed away with runoff, then swept into lakes, rivers and oceans. Here, phosphorus is the limiting nutrient controlling the growth of algae (Vaccari, 2009). The photosynthetic microbes form huge, unnatural blooms, which then die off and prevent sunlight from reaching delicate aquatic ecosystems at greater depths. This phenomenon, known as eutrophication, creates huge, seasonal "dead zones" in areas like the Gulf of Mexico, the Great Lakes, and China's coastal waters (Tirando, 2008).

Geology and Mining

Phosphorus is not found as a free element in nature, but naturally occurs as phosphate minerals, which are mined to produce phosphoric acid (FIPR, 2010). One complicating issue with phosphorus is that high-grade ore deposits are highly geographically segregated. That is, they occur in specific regions within the boundaries of very few countries, even fewer and more concentrated than natural fossil fuels. According to the USGS, more than 70% of the world's known supply of phosphorus is located in Morocco and the western Sahara. Another 16.5% lies in Iraq, China, and Algeria, with the rest spread out between Russia, the United States, South Africa, Jordan, Syria, and a few others. (Jasinski, 2012). As known supplies grow scarce and the burden of production falls on fewer and fewer countries, international disputes and even violent conflicts are a distinct, frightening possibility.