Scientists at the UK Centre for Ecology & Hydrology (UKCEH) have contributed to the first global agreement to reduce nitrogen waste, which has adverse impacts on human health, biodiversity and climate change. 

Nitrogen is essential to the growth of plants and a key building block of DNA. But inefficiencies in food production, transport, energy, industrial and wastewater processes mean 80 per cent of the compound used, worth about US $200 billion, is lost to the environment. This means reactive nitrogen is, in its various forms, a significant air and water pollutant and greenhouse gas. 

A resolution to accelerate efforts to reduce this waste globally by 2030 and beyond through sustainable nitrogen management was universally adopted by the UN Environment Assembly (UNEA), made up of representatives from 193 countries. The resolution had been put forward by the Ministry of Environment of Sri Lanka, which received technical advice from Professor Mark Sutton of UKCEH as a member of the country’s delegation to UNEA in Nairobi. It was co-sponsored by Brazil, Maldives, Pakistan and Uganda.

The global resolution is a direct outcome of regional leadership developed as part of the South Asian Nitrogen Hub funded by the UKRI Global Challenges Research Fund.  

Prof Sutton says: “This landmark decision is a big step towards our ambition of halving global nitrogen waste, which would have benefits for the environment, human health and economies, and support progress towards multiple UN Sustainable Development Goals.”

Ammonia (NH3) from animal waste and nitrogen dioxide (NO2), emitted by motor vehicles and aircraft, are key components of airborne particulate matter which can aggravate respiratory and heart conditions and cause premature deaths. Nitrate from synthetic fertilisers, manure and industry pollutes rivers, seas and soils posing a health risk for humans, fish, coral and plant life. Overuse of fertilisers, fossil fuel burning and industrial processes produce nitrous oxide (N2O), a potent greenhouse gas.

However, some farmers in parts of Africa and Asia struggle to access sufficient nitrogen for crop cultivation, thereby limiting food production and risking soil degradation.

There are a wide range of options for better nitrogen management, which the UNEA resolution will help mobilise with Member States in the years ahead through the  Nitrogen Working Group of the the UN Environment Programme (UNEP). This work will be supported by the research of a Global Environment Facility/UNEP project, Towards an International Nitrogen Management System (INMS) directed by Prof Sutton.  

The INMS activity includes assessment of actions relevant for arable and livestock farming, waste management and vehicle emissions. Examples include better management of manure and more efficient use of chemical fertiliser to reduce air pollution and runoff into waterways, as well as improving the recovery and reprocessing of nitrogen in wastewater so it can be reused in agriculture.

Prof Sutton comments: “If you can smell your manure heap, it means it is already losing its goodness to the atmosphere. It is much better to cover all manure resources, keeping volatile nitrogen compounds where we want them: helping farmers to maximise crop yields.”  

Sri Lanka Environment Minister Mahinda Amaraweera says: “Nitrogen is a big issue for our planet that has been ignored for too long.”

The UNEA resolution follows the 2019 Colombo Declaration, where 15 countries agreed to work towards the goal of halving nitrogen waste, which, globally, would save the equivalent of US $100 billion a year.

Further information

Prof Sutton provided support to Sri Lanka at UNEA in cooperation with Clare Hamilton of Tallavey Sustainability, a UKCEH partner supported by INMS, who contributed specific expertise on UN treaty law. The Sri Lankan negotiating team for the resolution was completed by Dr Anil Jasinghe, Secretary, Ministry of Environment; Ms Janaki Amaratunge, Director of International Relations, Ministry of Environment; and Prof SP Nissanka of the University of Peradeniya.