As an essential plant nutrient in fertilizers, phosphorus is central to food security and societal development. Derived predominantly from phosphate rock, it is converted into a range of fertilizer products including diammonium phosphate (DAP), monoammonium phosphate (MAP) and triple superphosphate (TSP). Around 85% of the phosphate rock reserves are located in five countries: Morocco (70%), China (5%), Egypt (4%) Algeria (3%), and Syria (3%) (Jasinski, 2022). Based on recent annual mining production rates, phosphate rock mining is dominated by four countries: China (39%), Morocco (17%), the USA (10%), and Russia (6%) (Jasinski, 2022). By contrast, nitrogen for fertilizers comes from the atmosphere and can be produced by any country with a sufficient energy supply. In some regions, poor access to mineral phosphorus is already pushing food security targets further from reach (Brownlie et al., 2021). It was previously estimated that 1 in 7 farmers could not afford sufficient fertilizers to meet crop requirements, impacting their ability to produce food (IAASTD, 2009).

In contrast, nutrient pollution through fertilizer overuse and insufficient wastewater treatment, can trigger toxic algal blooms and create coastal dead zones threatening human and animal health (Bajželj et al., 2014). These effects will be exacerbated by climate change. Emerging evidence also suggests that anthropogenic phosphorus enrichment of lakes will contribute to climate change through the greenhouse gas emissions associated with enhanced eutrophication (Downing et al., 2021). Controlling the phosphorus lost to freshwaters from anthropogenic sources globally would cost ~US$265 billion per year (Johnes et al., 2022). Currently, the economic losses of eutrophication are paid by society through losses of ecosystem services. If phosphorus pollution of the aquatic environment is not reduced in the coming years, the environmental and socio-economic impacts may be irreversible (Carpenter and Bennett, 2011).

It has been suggested that agricultural phosphorus demand may double by 2050, compared with 2006 (Mogollón et al., 2021). This is a consequence of national to global scale demands for food and non-food goods, some of which are destined for international trade (Hamilton et al., 2018). These demands are embedded within national economic development plans and are often not aligned with global sustainability policy agendas. In a business-as-usual scenario, global phosphorus requirements will overtake global phosphorus supply after 2040 (Nedelciu et al., 2020).

No global policy exists for phosphorus. Business as usual for phosphorus ignores the impacts of degraded natural capital on the growth of the green economy (Dasgupta, 2021). It neglects the value of circularity in the anthropogenic phosphorus cycle, where currently <50% of phosphorus wastes/residues are recycled back into the global food system (Brownlie et al., 2021). Finally, it fails to recognize that phosphorus vulnerability is driven, in part, by the international trade of food and non-food goods, creating a novel transboundary context to nutrient impacts across aquatic ecosystems (Hamilton et al., 2018).

Current elevated phosphorus commodity prices are starting to bring phosphorus vulnerability to political and public attention. Phosphorus vulnerability can be described as the degree to which people/systems are susceptible to harm due to the physical, geopolitical and socio-economic dimensions of global phosphorus scarcity and pollution (Cordell and Neset, 2014). It is an interaction between exposure (the degree people and food systems are exposed to external shocks like phosphorus commodities price spikes), sensitivity (the degree of harm caused by exposure) and the adaptive capacity of people and institutions to mitigate harm by reducing exposure or sensitivity (Cordell and Neset, 2014). The components of phosphorus vulnerability are diverse and work at different temporal/geographical scales. For example, water quality degradation resulting from insufficient phosphorus management (i.e., adaptive capacity) is chronic for all nations (Johnes et al., 2022). Spikes in phosphorus commodity prices (i.e., exposure) are episodic with short-term global food security impacts. In economically under-developed countries, phosphorus access issues are an enduring risk to food security (i.e., sensitivity).

The current price spike is raising concern that farmers will not be able to access sufficient phosphorus to produce food using existing farming systems (UN GCRG, 2022; World Bank Group, 2022). As stated by the President of the World Farmers Association, in May 2022 (de Jager, 2022), “whether in North America or Oceania, even in Ukraine and Russia, the main talk amongst farmers is fertilizers, the availability and the price.”

Three major spikes in phosphorus commodity prices have occurred in the last 50 years, in 1975 (>700%), 2008 (by 800%) (Brownlie et al., 2022a), and 2020-22. In 2008, escalating phosphate prices eventually crashed with prices stabilizing at double that of pre-2007 prices. While it was linked more broadly to the global economic crisis of the time, the specific contribution of different causes of the 2008 price spike remains unclear and likely driven by several interacting factors. These included changing market supply and demand dynamics for agricultural and phosphorus products, instability in energy prices and geopolitical control on exports (International Fertilizer Industry Association, 2011). Long-term (multi-decadal) factors included income growth and dietary changes in emerging economies (e.g., increasing consumption of animal products in China and India, which requires more phosphorus to support); competing objectives for agriculture, in addition to food and feed production (e.g., production of fiber, biofuel feedstock and bio-chemicals); global grain market conditions (i.e., low cereal stocks); and background increases in energy prices (Brownlie et al., 2022a). Short-term (interannual) factors included economic weakness in many countries, export restriction measures, extreme weather conditions and natural disasters (International Fertilizer Industry Association, 2011). Some reports suggest the introduction of a US ethanol policy and increases in food prices in 2008 contributed to increased phosphorus demand (Cordell et al., 2015). Others argue the major contributor was an Indian Government fertilizer subsidy scheme which caused a doubling of fertilizer imports (Khabarov and Obersteiner, 2017). In 2008, China applied an export tax of 100–135% on domestically produced phosphate fertilizers, effectively halting exports (de Ridder et al., 2012). This was driven by an increase in national agricultural production and by concerns that Chinese phosphate rock reserves were being overexploited.

Similarly, a perfect storm of drivers is being attributed to the most recent (2020–22) and ongoing price increase in phosphorus commodities (Cross, 2022):

In response to phosphate market disruptions in 2020–22, several governments implemented “knee-jerk” policies to protect domestic markets (Figure 1). In March 2021, the US International Trade Commission determined that the low price of phosphate fertilizer imports from Morocco and Russia had affected the US market and placed tariffs of 9–47% on phosphate fertilizer imports (Quinn, 2021). In May 2021, India increased subsidies for DAP fertilizer by 140% to protect farmers from increasing fertilizer costs. In October 2021, China (the second-largest fertilizer exporter in 2020 by value; US$ 6.57 billion in 2020) stopped all exports further constraining global supply and accelerating price rises. Countries dependent on China for supply (e.g., Australia, India, Pakistan and countries in South-East Asia, and the USA) have been forced to reduce imports or import from elsewhere. In November 2021, Turkey placed export restrictions on phosphate fertilizers further tightening the market. In March 2022, Russia (the largest fertilizer exporter by value; US$ 7 billion) suspended fertilizer exports, asserting sanctions were impacting international shipping. Nevertheless, phosphate prices had already increased substantially before 24 February 2022 (Figure 1). As observed in 2008, multiple short-term government responses designed to protect national interests can simultaneously disrupt global phosphorus trade and increase phosphorus exposure on a global scale. The immediate effects on different phosphate forms also appear to be different, with price changes in phosphate rock lagging several months behind DAP and TSP fertilizers (Figure 1).

It is a matter of shared global interest to reduce unpredictable phosphorus price volatility. There are many opportunities for action. For example, international diplomacy could encourage countries to lift phosphorus export restrictions and avoid new ones. Current restrictions are estimated to be impacting 20% of the global fertilizer trade and threaten more than 50% of the fertilizer supply for 24 countries (Hebebrand and Laborde, 2022). Whilst elevated prices persist, governments would be well-advised to review financial support for farmers in tandem with support to optimize on-farm nutrient use efficiency (Masso et al., 2022). It can be argued that the international community has a moral responsibility to support lower-income countries to access sufficient phosphorus to maintain domestic food production (Kahiluoto et al., 2021). Where international aid is appropriate, it should aim to avoid contributing to inflation, and for countries under severe economic stress, financial support may be grant-based to minimize further debt creation (Hebebrand and Laborde, 2022).

A further opportunity for governments is to explore how International Commodity Agreements can be used to protect food security in developing economies with high market exposure (Oehl, 2022). This could be driven by a “fair and equitable benefit-sharing” approach, following examples adopted for other natural resources including marine resources, land use, forest and water management, food production and other extractive activities (Morgera, 2016). Here, we would envisage the application of multi-lateral and bilateral deals, which could for example secure a stable phosphorus supply to vulnerable nations that do not have domestic phosphorus supplies, in exchange for securing agricultural exports from those vulnerable countries. Such multilateral deals may be moderated through an international organization (e.g., The World Trade Organization). A benefit-sharing approach for the trade of phosphorus may not directly mitigate the effects of phosphorus pollution on the environment. However, benefit sharing of transboundary waterbodies may require upstream water users to better manage their phosphorus pollution to avoid polluting shared water bodies, and in this way mitigate phosphorus pollution. In addition, the development by the financial sector of a sustainable investment strategy for the phosphorus mining/fertilizer sector (e.g., as established for the fossil fuels sector) could help enable fair and ethical supplies of affordable phosphorus fertilizers for use where it is needed (Schütze et al., 2017).

However, to mitigate the impacts of phosphorus pollution and future phosphorus price spikes, strategies that deliver long-term resilience to phosphorus vulnerability are required.

We highlight three opportunities that could build long-term resilience nationally and internationally to phosphorus price volatility and regional food and water insecurity (Figure 2).

Overall, it can be concluded that the current crisis in global phosphorus prices represents a wake-up call on the underlying problems of phosphorus pollution. The price spikes have been triggered by a combination of uncoordinated national decisions and are impacting food security in vulnerable communities and countries, compounding the existing food and energy crises. Whilst several short-term measures could be implemented to alleviate farmer and food insecurity in these nations (e.g., increasing fertilizer subsidies), we argue that investing in longer-term transformative phosphorus initiatives, as described above, would not only create more resilient food and water systems but also reduce the impact of short-term phosphorus risks in the future. The necessary knowledge is already available and being applied by some countries in longer-term plans to build greater resilience to phosphorus vulnerability (Brownlie et al., 2021; Barbieri et al., 2022). However, these green shoots of progress must now be planted across all countries.

WB co-conceived the idea of the manuscript and led the writing of the paper, and collated and conducted data analysis. MS, DC, DR, KH, PW, and IV contributed to writing the paper. BS co-conceived the idea of the manuscript and contributed to writing the paper. All authors contributed to the article and approved the submitted version.