Could another Guano War develop?

A significant portion of Chapter 7 in What Things Are Made Of is devoted to phosphorus and phosphate rock, the building blocks of fertilizer and critical for life. The term “peak phosphorus” is only about four years old, but together with rare earths and lithium, global phosphorus supply is gaining mainstream attention.

While some research suggests phosphorus supplies could decline to problem levels by 2035, a recent analysis takes a different view. Either way, irregular distribution—one of the themes of my book—will probably impact phosphorus trade and use.

Phosphate rock ooids from Montana. Photo by Richard Gibson

In 2010, the U.S. imported 15% of its phosphate rock, the highest import dependency in history. The United States was a net exporter most years until about 1997, and imports were generally small until 2010, in part a reaction to the apparent ending of the global recession. All U.S. phosphate rock imports came from Morocco—the little country that owns or controls about three-quarters of the world’s reserves. Morocco and the U.S. produce about equal amounts, at 26 million tons per year (about 15% of world production each). China leads the world in phosphate rock mining with 37% of the total.

The mineral apatite, calcium phosphate, forms phosphate rock. Exactly how these deposits arise is still somewhat questionable, but upwelling ocean currents are thought to allow the chemical precipitation to occur. Other economic phosphate deposits are bird guano; islets off Peru covered with such material contributed to the “Guano War” in the 1860s. Whether demand for phosphate will lead to anything beyond trade wars remains to be seen.