image: The new international guidance document, Nitrogen mitigation, goes beyond agriculture, which is the largest consumer and emitter of nitrogen, to consider all economic sectors, and addresses the issue on a global scale.
Credit: INMS
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200bn tonnes of nitrogen are lost to environment globally every year, equivalent to up to $300bn (US dollars).
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Online toolkit outlines range of sustainable practices for different sectors to cut pollution of air, water, soils.
The most comprehensive scientific review of the global nitrogen cycle has outlined 150 ‘win-win’ measures to significantly reduce nitrogen pollution while saving billions in costs across a range of industries.
The solutions have been put forward by a team of 50 international experts, led by the UK Centre for Ecology & Hydrology (UKCEH), in a new guidance document for the United Nations. They aim to address the problem of excessive nitrogen leakage that is damaging our oceans, lakes, air and soils, while improving food security and reducing costs for business.
Nitrogen, an essential nutrient for life, is present in human and animal excreta and synthetic fertilisers, as well as being a byproduct of fuel combustion processes. However, inefficient management in sectors such as agriculture, transport, wastewater treatment and aquaculture, means around 80% of reactive nitrogen resources escape into the environment.
Nitrogen in its various forms – including ammonia, nitrogen oxides, nitrate and nitrous oxide – can result in poor air quality that threatens human health, toxic algal blooms that cause the death of plants and fish in oceans and lakes, and increased climate change.
Providing a toolkit
The new international guidance document, Nitrogen mitigation, goes beyond agriculture, which is the largest consumer and emitter of nitrogen, to consider all economic sectors, and addresses the issue on a global scale.
The authors have also produced an online toolkit, the Nitrogen Measures Database, which is designed to be used alongside the guidance document and provides further detail on each measures including ‘how to implement’ and the cost, benefits and risks of implementing each measure. This will support policymakers and stakeholders to select the most suitable measures for their specific requirements and ambitions.
The international guidance document considers synergies and trade-offs between actions and features case studies to demonstrate how a package of measures can be selected.
Key recommendations
The recommended actions include:
- Improved fertiliser use. More efficient storage and application of organic and synthetic fertilisers, which would reduce pollution, energy consumption and costs for farmers.
- Sustainable farming practices. Using cover crops and reducing tillage to retain nitrogen in soils. Integrating livestock and arable farming where possible. Keeping animal housing clean.
- Natural filtration systems. Constructing wetlands to keep nitrogen pollution out of lakes and rivers.
- Nitrogen recovery. Improving treatment of sewage and food waste to recover nitrogen, which can then be added as a fertiliser to fields.
- Sustainable fish farming. Applying nutrient-rich sludge from fish farms to agricultural land as a fertiliser using low-emission techniques.
- Reducing transport emissions. Increasing the use of electric vehicles and improving fuel combustion processes, and recovering nitrogen oxides for their nitrogen value.
- Dietary changes. Cutting food waste and consumption of animal products with high nitrogen footprints.
- Energy generation from organic residues. Using anaerobic digestion to process manure and aquaculture sludge into biogas, with the byproducts retained for use as fertiliser.
The cost of nitrogen waste
Scientists estimate 200 billion tonnes of nitrogen is lost to the environment globally every year, which, if equated with the wastage of the same amount of fertiliser, is equivalent to a loss of up to 300 billion US dollars at current prices.
Benefits for people and planet
Dr Will Brownlie, lead author of Nitrogen mitigation, says: “Improving nitrogen management offers a remarkable opportunity to not only enhance environmental health but also strengthen the global economy. The key lies in adopting an integrated approach across the entire nitrogen cycle, ensuring that all sectors involved have access to the diverse strategies available to improve nitrogen sustainability.”
The guidance document, produced by scientists representing 40 institutes in 21 countries, points out that sustainable nitrogen management is crucial to achieving most of the UN Sustainable Development Goals.
Retaining more nitrogen within the agricultural system would improve food security, especially in regions where nutrient-poor soils limit crop production.
Sustainable management of nitrogen would also help mitigate climate change, by reducing nitrous oxide emissions.
Circular economy
The report advocates using data collection, satellite monitoring and artificial intelligence, combined with smartphone technologies, to provide accurate, site-specific nitrogen management guidance.
Professor Mark Sutton of UKCEH, who leads the International Nitrogen Management System (INMS) emphasises: "We are delivering innovative science-based guidance for the UN to accelerate uptake globally. Our vision is for a circular nitrogen economy that wastes less of this precious resource, reducing the costs to governments, farmers and wastewater companies, while boosting farmers’ incomes."
Isabelle van der Beck of the United Nations Environment Programme (UNEP) adds: "INMS is highlighting the importance of nitrogen as as a multi-dimensional challenge that links all economic sectors. We see this as a way to mobilise efforts to reduce international water pollution, so we can simultaneously benefit air, climate, biodiversity and the economy."
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Notes to Editors
About the guidance document
Nitrogen mitigation has been produced as part of the International Nitrogen Management System (INMS) initiative.
The Nitrogen Measures Database, which is designed to be used alongside the Nitrogen Mitigation guidance document, is available here.
INMS comprises around 80 partners globally, providing evidence on the nitrogen cycle, impacts of pollution and solutions. It is funded through the Towards INMS project by the Global Environment Facility (GEF), through the United Nations Environment Programme (UNEP).
The INMS Guidance Document and online tool will be launched on 25 September 2024 at the 10th International Waters Conference (IWC10) organised by the GEF, which runs 23-26 September at Punte del Este, Montevideo, Uruguay.
About nitrogen
Nitrogen is a naturally occurring element that is essential for life. Unreactive nitrogen gas (N2) makes up 78 per cent of the air we breathe.
However, in reactive forms, it is a pollutant of air, water and soils:
- Gases such as ammonia (NH3) and nitrogen oxides (NOx) are key components of particulate matter, thereby contributing to poor air quality which can aggravate respiratory and heart conditions, leading to premature deaths.
- Nitrate from chemical fertilisers, manure and industry pollutes rivers, seas and soils posing a health risk for humans, fish, aquatic organisms and plant life.
- Nitrous oxide (N2O) is a greenhouse gas that depletes the ozone layer and is 260 times more powerful than carbon dioxide