Peak phosphorous: mankind's latest threat

Some believe that dwindling supplies of potable water is humanity’s great resource challenge; others think it is the imminent prospect of “peak oil”.

But an equally important milestone in modern history will be an inevitable tightening of global supplies of phosphorus.
Phosphorus has underpinned the leaps made in agricultural productivity since World War II, and the world’s economies and population levels have become dependent on a continous supply of the element.

Unlike nitrogen, which can by synthesised from the air, or the use of renewable energy to substitute for fossil fuels, there is no substitute for phosphorus. All the world’s phosphate fertilisers come from mined phosphate rock, making it a finite resource.

Various analyses suggest “peak phosphorus” – the point at which supply falls behind demand – will occur around 2040, with all currently known reserves potentially exhausted within 50 to 100 years.

However, University of Technology Sydney researchers Dana Cordell and Stuart White warn that for most countries, a phosphorus squeeze is likely to come much sooner.

Demand for phosphorus is growing in line with population growth, and is being pushed higher by greater consumption of meat in countries like China and India.

(Based on European practices, the Swedish Environmental Protection Agency estimates that a vegetable-based diet uses 0.6 kilograms of phosphorus per person per year, compared with 1.6 kg for a meat-based diet.)

Few nations have access to enough phosphorus to supply their own agricultural needs: in fact, most of the world’s known phosphate reserves are controlled by China, the United States and Morocco.

China has the largest reported reserves, but in 2008, at the height of the food crisis, China’s central government introduced a 135 per cent tariff on exports to protect domestic supply.

The US, historically the world’s largest consumer, importer and exporter of phosphate fertilisers, is now thought to have only about 25 years of domestic phosphate reserves left. US fertiliser manufacturers are importing large quantities of phosphate from Morocco.

Stock & Land