Assessing the global phosphorus cycle and opportunities for closing the loop

Phosphorus (P) and phosphate rock have been included in the list of EU’s critical raw materials, due to their importance in agricultural production and food security. However, over the latter 20th century and up to today, P use in agriculture has increased much faster than population growth (from 4.5 Tg P and 3.0 billion people in 1961 up to 18 Tg P in 2022 and 8.0 billion people in 2022)¹. These growing inefficiencies in global phosphorus use are coupled with a linearized economic model of produce, use, waste, completely short circuiting the global phosphorus cycle. Indiscriminate use of P (has increased global P cropland soil stocks by over 1 Pg P over the aforementioned time period, despite cropland soils having over 100 Tg Olsen P (readily available P)². Conversely, in many low-income nations, a volatile phosphorus market (a doubling and a halving over the past 5 years) is leading to disruptions in their phosphorus supply chain and threatening their food security. In addition, humanity’s changes to the phosphorus cycle are leading to both upstream pressures for phosphorus fertilizer production, including millions of tons of phosphogypsum waste, and downstream eutrophication pressures, as phosphorus is a limiting nutrient in many aquatic environments.

 

Nevertheless, increasing scientific understanding of the global phosphorus cycle, plant-nutrient interactions and mycorrhizal network, the biogeochemical interactions of P in aquatic and soil environments, phosphorus recovery and immobilitzation from wastewater and from eutrophic systems, is growing in to a strong, yet fragmented phosphorus community. Further, clear policies and regulation for phosphorus use and recovery on for closing phosphorus loops are lacking at a global level. This presentation will showcase some low-hanging fruits that can help us move toward a closing of phosphorus loops by highlighting local phosphorus balances, food and fertilizer phosphorus use and trade patterns, soil phosphorus stocks, and potential for eutrophication. Finally, it provides a call to bring together European scientists, food producers, the waste(water) sector, and policymakers together to form a coalition that can move phosphorus toward circularity, ameliorating its environmental impacts, and ultimately establishing a resilient and sustainable global food system.

 

¹Mogollón, JM, Bouwman, AF , Beusen, AHW, Lassaletta, L, van Grinsven, HJM, Westhoek, H. (2018) More efficient phosphorus use can avoid cropland expansion

Nature Food, 2, 509-518.

 

²McDowell, RW, Noble, A, Pletnyakov, P, Haygarth, PM (2023) A global database of soil plant available phosphorus, Scientific Data, 10, 125.