Queen’s University Belfast: Scientists offer solutions to global phosphorus crisis that threatens food

Phosphorus is an essential but often overlooked resource, which is vital for life on Earth and is extracted from phosphate rock for use in crop fertilisers, livestock feeds and food additives.

Global food security remains threatened as many farmers struggle to afford sufficient phosphorus fertiliser for their crops. Meanwhile, overuse of fertilisers and sewage pollution pump millions of tonnes of phosphorus into lakes and rivers each year, damaging biodiversity and affecting water quality.

The Our Phosphorus Future report is the most comprehensive global analysis of the challenges and possible solutions to the phosphorus crisis to date. It has been written by a team of 40 international experts, including researchers from Queen’s University Belfast. The experts from 17 countries have been led by the UK Centre for Ecology & Hydrology (UKCEH) and the University of Edinburgh, and the research is supported by the United Nations Environment Programme (UNEP).

The report calls on governments across the world to adopt a ’50, 50, 50′ goal: a 50 per cent reduction in global pollution of phosphorus and a 50 per cent increase in recycling of the nutrient by the year 2050.

Recommendations in Our Phosphorus Future include:

integrating livestock and crop production so phosphorus in animal manure is applied to crops, reducing the demand for chemical fertilisers;
moving towards more sustainable diets, which would reduce the amount of phosphorus needed to grow animal feed;
reducing global food waste, meaning less demand for crops and animal products, and therefore phosphorus (a recent UNEP report estimated global food waste from households, retail establishments and the food service industry totals 931 million tonnes each year);
improving wastewater treatment to remove phosphorus from sewage, so it can be reused and does not enter lakes and rivers.
Only four countries control around 70 per cent of the annual global production of phosphate rock from which phosphorus is extracted, leaving the market exposed to massive fluctuations in costs and supply due to political disputes, trade wars and escalating fuel prices. Since 2020, for example, the prices of both phosphate rock and fertiliser have increased by around 400 per cent, and continue to rise. This instability exacerbates the impacts of other global factors influencing fertiliser costs, such as the effect of the war in Ukraine on the cost of natural gas.

Professor John McGrath, from the School of Biological Sciences at Queen’s University, said: “Resource security is a key issue for the Northern Ireland economy. Domestic and industrial effluent or agri-food by-products can no longer be categorised as waste but must be considered as valuable resources that can be converted into high-value bio-products such as phosphorus. Recycling phosphorus from waste will not only be more sustainable and provide increased resilience for our food systems, but it will also help protect the environment by reducing pollution in rivers and lakes.”

Professor Bryan Spears of UKCEH, one of the lead authors of the Our Phosphorus Future report, says: “Many countries are highly dependent on imported phosphorus fertiliser for food production, leaving them exposed to fertiliser price fluctuations. More efficient use of phosphorus in agriculture and increased recycling, for example from wastewater, can increase resilience in the food system while reducing pollution of lakes and rivers that are biodiversity hotspots and important for drinking water supply.”

The report’s authors estimate adopting the ’50, 50, 50′ goal would create a food system that would provide enough phosphorus to sustain over four times the current global population, save farmers nearly US $20 billion in annual phosphorus fertiliser costs and avoid a projected yearly clean-up bill of over US $300 billion to remove phosphorus from polluted water courses.

Phosphorus pollution in lakes, rivers, and coasts accelerates the growth of algal blooms which produce toxins that are harmful to animals and humans who come into contact with or consume contaminated water. The cost of responding to water-based phosphorus pollution in the UK alone is estimated at £170 million per year.