Runoff to water streams of nutrients such as phosphorus increases the intensity of algal blooms. The ... More picture above shows an aerial view of green water during a harmful algal bloom (HAB) on 25 August 2022 in Lake Elsinore, California. The city closed the lake to all activities, including fishing, swimming and boating, due to the danger of serious illness or death in humans and animals. California is experiencing some of the worst HAB outbreaks in the nation, with an increase of more than 464 percent in epidemics in the past five years. (Photo by David McNew/Getty Images)Getty Images Phosphorus is a nutrient most people rarely think about. Yet it touches almost every aspect of our lives—the food we eat and the water we drink. One of its most common uses is in the form of fertilizers used for agriculture, but it is also naturally found in manure. In reasonable quantities, it helps plants grow and supports the ecosystem, but phosphorous overuse is a menace. Globally, phosphorous use is expected to double, overshooting the safe planetary boundary. The current global phosphorus use is 17 million tons per year and is expected to reach 32.5 million tons, far exceeding the safe global planetary boundary of 11 million tons annually. Crossing this boundary puts environmental stability and food security at risk. Most fertilizers used for agriculture contain phosphorus derived from phosphate rocks. Due to the overuse of such fertilizers, our planet’s natural phosphorus cycle is under pressure and cannot absorb as much. One significant consequence is eutrophication—when far too many chemicals, including phosphorus, runoff from farms into waterways. This situation causes an overgrowth of algae, which prevents oxygen from reaching marine life. Addressing this problem is a costly affair. For instance, it costs the US economy $2.2 billion annually and England and Wales in the UK $105–160 million annually. Algal blooms are becoming more frequent with rising temperatures. In recent years, water bodies in US states like Oregon—such as the Willamette River—have developed thick layers of green algal blooms every summer. Last month, lawmakers asked for $1 million to fund a university project that would stop toxic algal blooms through engineering solutions. However, this does not address the root of the problem—which is cutting the overuse. Despite the urgency of addressing the phosphorus problem, bringing sustainability to this supply chain hasn’t received as much attention. Discussions on this chemical are often clubbed with other chemicals or nutrients, such as nitrogen, although there is a uniqueness to these chemicals. For instance, phosphorous is a finite natural reserve and can be recycled. There is thus a need to raise targeted awareness and debate about phosphorus. With that intention, we look at some things that must be done to ensure future phosphorus sustainability. 1. Agriculture And Food Industry Must Address The Phosphorus Overuse Agriculture and the food industry are among the biggest consumers of phosphorus, and it is vital to change the status quo in this industry. Improving phosphorus use efficiency in farms is essential, which means addressing the problem of applying too much phosphorous through fertilizers or manure and ensuring the lost phosphorous through the waste streams is recycled back to farms. This was one of the key recommendations of a report, Our Phosphorus Future: Towards Global Phosphorus Sustainability, in which over 100 scientists explored this topic in great detail. Around 85% is used for fertilizers, 10% for animal feed, and 2–3% for food additives. Currently, most regulations that address phosphorus runoff cover sources that can be easily identified, such as discharge pipes. However, rules are loose for non-point sources —runoff that cannot be attributed to a single source. Such sources often include runoff from fields or surrounding areas to flow into the water streams. Even when stringent regulations are in place in some countries, sometimes enforcement remains weak. Last year, a subsidiary of Cargill, a company that produces large-scale poultry, was sued alongside other poultry companies for the pollution caused by the manure from 23 million chickens that spread on the land in the catchment area near River Wye in the UK. The manure produced by such big companies is by no means small. The largest food companies produce manure equivalent amounts to entire countries; for instance, according to an estimate, Tyson, a big livestock company in the US, makes as much manure as 431 million people, roughly the size of the USA. While most of these companies conduct water quality assessments, they are not thorough enough, as they do not include animal and feed supply chains, according to Maria, a technical specialist at FAIRR Initiative, an investor network that raises awareness of the material risks and opportunities in the global food sector. At the same time, it is essential to note that some regions still do not have access to enough phosphorus. Data from a global analysis of agricultural inputs shows regional variations in phosphorus use on farms worldwide. Some countries also have a phosphorus deficit, including many countries in sub-Saharan Africa. According to the above report cited above, one in seven farmers cannot access or afford phosphorous fertilizers, reducing their ability to maintain food security and livelihoods. 2. Governments Must Strengthen Regulations For Phosphorus Efficiency The other side of tackling phosphorous overuse is improving its efficiency— and that is a problem that can be solved. Some farmers in countries like India and China are building phosphorus reserves in their farms in recent decades. Such reserves enable them to grow subsequent crops on the same land without further phosphorus-based fertilizer application. To improve efficiency in phosphorous recycling, the Government should reach a consensus on an international agreement. The agreement should also include ambitious targets to recover and recycle nutrients from livestock manure, wastewater, and industrial waste streams. Although there are international agreements supporting the sustainable use of chemicals—such as nitrogen—a similar deal for phosphorus is much needed but not yet in place. During the fourth session of the United Nations Environment Assembly, over 20 resolutions were passed, many of which had implications for phosphorus. However, a direct agreement explicitly focused on this chemical is needed. Such an agreement is also needed to help address future concerns about food security linked to limited phosphorus reserves. Most phosphorus reserves are concentrated in a handful of countries, creating a problematic situation for future food security—just five countries account for 85% of the world's phosphorous reserves. Morocco, China, Algeria, Syria, and Brazil are the top countries with phosphate rock reserves. It is estimated that 85% of phosphate mined from phosphate rocks produces fertilizers. 3. Scaling Up The Market For Recycled Phosphorus Products Is Crucial Unfortunately, phosphorus resources recovery efforts have not scaled up—and this is where the private sector has a role. Some startups are working in this space, but momentum is now needed. Just a month ago, a woman-led startup in the UK won an Innovate UK Women in Innovation Award for her role in setting up a project that moves phosphorus from lakes and rivers—where it causes damage—to farmlands where it can be used for crops. Making recovered phosphorus commercially viable requires patience. Experts in the report cited above argue that recovered phosphorus cannot be compared with the same yardstick as other substitutes especially on the cost point. Currently, the market is trying to address the challenge of producing enough volume and maintaining a uniform quality. Until this nascent market for recovered phosphorus becomes more mature, all stakeholders in the ecosystem need to share the responsibility. There is also potential to share the recovery cost in more developed markets. As we consider a sustainable future, it is essential that phosphorus overuse which can significantly impact our planet’s health, marine life, and water streams so much—receives targeted attention. A sustainable phosphorus future requires action now.