The Solutions
Nitrogen pollution of air, water and soils is severely damaging to public health, biodiversity and ecosystems, and exacerbates climate change. The systemic nature of reactive nitrogen means that sources and impacts are interrelated - it cannot be managed in silos, so the first step to reducing nitrogen pollution is taking a system-wide approach using an integrated government strategy. Taking account of the nitrogen system as a whole, and the interrelated nature of processes and flows, will enable co-benefits to be achieved and unintended consequences to be avoided.
UK National Targets & International Commitments
Biodiversity
Water
Reduce nitrogen pollution from agriculture into the water environment by at least 40% by 2038, compared to a 2018 baseline, with an interim target of 10% by 31 January 2028, and 15% in catchments containing protected sites in unfavourable condition due to nutrient pollution by 31 January 2028.
Restore 75% of our water bodies to good ecological status.
Biodiversity
Halt the decline in species abundance by 2030, and then increase abundance by at least 10% to exceed 2022 levels by 2042.
Restore or create more than 500,000 hectares of wildlife-rich habitat by 2042, alongside our intentional commitment to protect 30% of our land and ocean by 2030. With an interim target to restore or create 140,000 hectares of wildlife-rich habitats outside of protected sites by 2028, compared to 2022 levels.
New interim targets for all sites of special scientific interest (SSSIs) to have an up-to-date condition assessment; and for 50% of SSSIs to have actions on track to achieve favourable conditions by 31 January 2028.
Increase tree canopy and woodland cover from 14.5% to 16.5% of total land area in England by 2050, with a new interim target to increase this by 0.26% (equivalent to 34,000 hectares) by 31 January 2028, in line with the trajectory required to achieve the long-term target.
For 70% of designated features in Marine Protected Areas (MPAs) to be in favourable condition by 2042 with the remainder in recovering condition, with a new interim target of 48% of designated features to be in favourable condition by 31 January 2028, in line with the trajectory required to achieve the long-term target.
International commitments
The UK also has an international commitment to the COP15 Kunming-Montreal Global Biodiversity Framework. Target 7 outlines a reduction in the negative impact of pollution from all sources by 2030, to levels that are not harmful to biodiversity and ecosystem functions and services including by reducing excess nutrients lost to the environment by at least half.
Health
Air Pollution
A legal target to reduce population exposure to PM2.5 by 35% by the end of 2040 compared to 2018 levels, with an interim policy target to reduce by 22% by the end of January 2028
Current legal limits on nitrogen dioxide include an annual average concentration limit of 40µg/m³ for nitrogen dioxide (NOâ‚‚). The World Health Organisation’s updated air quality guidelines recommend a much stricter limit for NOâ‚‚ of 10 µg/m³, but the UK government is yet to adapt national targets to this level.
A legal target to limit maximum annual mean concentrations of PM2.5 to 10µg/m³ by 2040, with an interim policy target of 12 µg/m³ by the end of January 2028
Legal emission reduction commitments to reduce overall emissions of several nitrogen-related damaging pollutants across the UK by 2030 relative to 2005 levels:
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Reduce emissions of nitrogen oxides by 73%
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Reduce emission of PM2.5 by 46%
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Reduce emissions of ammonia by 16%
With emission reduction targets between 2000 and 2009:
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Reduce emissions of nitrogen oxides by 55%
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Reduce emission of PM2.5 by 30%
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Reduce emissions of ammonia by 12%
International commitments
The emission reduction commitments referred to above derive from the 1979 UNECE Convention on Long-Range Transboundary Air Pollution (the LRTAP Convention) and the 1999 Gothenburg Protocol to Abate Acidification, Eutrophication and Ground-level Ozone.
Climate
UK-wide legal target of net zero emissions by 2050, including carbon budgets 4, 5 and 6 from 2023 to 2037.
Montreal Protocol on Substances that Deplete the Ozone Layer.
As well as a policy commitment in the Net Zero strategy to consider how to reduce manufactured fertiliser.
Food
Through new farming schemes, bring at least 40% of England’s agricultural soil into sustainable management by 2028, and increase this to 60% by 2030.
Deliver a sustainable, nature positive, affordable food system that provides choice and access to high quality products.
International commitments
Target 10 of the GBF ensures that areas under agriculture, aquaculture, fisheries and forestry are managed sustainably, in particular through the sustainable use of biodiversity, including through a substantial increase of the application of biodiversity friendly practices, such as sustainable intensification, agroecological and other innovative approaches contributing to the resilience and long-term efficiency and productivity of these production systems and to food security, conserving and restoring biodiversity and maintaining nature’s contributions to people, including ecosystem functions and services.
The Solutions
Reducing nitrogen pollution relies on a progressive reduction of inputs going into the system, for example using nitrogen budgets at the farm and landscape level, to limit excess nitrogen entering the surrounding environment. These budgets could be nested within a national nitrogen budget, reducing nitrogen lost across the whole economy.
As a majority of nitrogen pollution is produced by the food system, transforming to a low-input system which focuses on harnessing ecological processes to provide fertility is paramount to reducing nitrogen pollution. Two important levers to achieve a food system transformation are dietary change and reducing the nitrogen imported through livestock feed and high-nitrogen products.
The final element of nitrogen reductions comes from reducing the reliance on fossil-fuel based energy inherent in industry, heating and transport.
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An integrated Government strategy
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Nitrogen budgets
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Land management practices
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Dietary change
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Imported food and feed
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Reducing emissions from combustion sources
An Integrated Government Strategy
Implementing successive system-wide reductions in nitrogen pollution requires an integrated approach by the Government to reduce nitrogen pollution in line with statutory national targets and international commitments. A comprehensive nitrogen use and reduction strategy would bring together the currently siloed policy and regulatory levers into one single systems-thinking framework.
The Government must raise the regulatory baseline of existing legislation in relation to all impact areas, enforcing the polluter pays principle to ensure nitrogen-related harms are properly accounted for. Effective government intervention requires a combination of regulation, education and fiscal measures to deliver reductions of nitrogen overuse and waste.
We recommend that the Government introduce a binding national strategy that places a duty on government departments and local authorities to meet more extensive nitrogen reduction commitments. Centering delivery on a systems approach would bring together all relevant policy areas and impact areas enabling co-benefits to be achieved and trade-offs to be identified and mitigated.
A systems approach would enable collaboration between and within local and central government, provided local authorities receive advice and guidance for achieving reductions in nitrogen pollution within their net zero strategy, planning or other strategies.
To set out a comprehensive plan would first require taking account of the nitrogen currently in the system, for example using a national nitrogen balance sheet. A nitrogen balance sheet is a quantification of nitrogen flows into and out of a geographical area within a given time period through the analysis of available data sources across the economy and the environment. Acting as an accounting tool of nitrogen stocks and flows across the environment and economy, it would allow identification of intervention points which would tighten the nitrogen cycle and increase nitrogen use efficiency. A balance sheet would inform and enable Government to set out pathways for reducing nitrogen use and waste across the economy and the environment, prioritising and balancing interventions to reduce wasted nitrogen from the biggest flows, and those that have the greatest co-benefits for a range of nitrogen related impacts.
The Sustainable Nitrogen Alliance has commissioned a UK Nitrogen Balance Sheet from Dragosits and Pearson, 2023. A new UK Nitrogen Balance Sheet (UK-NBS), Methodological Overview.
Nitrogen Budgets
Progressive reductions in nitrogen inputs are needed at the farm and landscape level, using nitrogen budgets to reduce overuse and waste of nitrogen resources and pollution. Calculated on a range of variables including the surrounding environmental and public health factors, a budget would use the balance sheet to set out progressively greater reductions of nitrogen flows, to reduce overuse and waste of nitrogen resources, and nitrogen-related pollution. The UNECE has published guidance on calculating national nitrogen budgets for sustainable nitrogen management.
Building the capacity of existing collaborations such as catchment panels and catchment based approach partnerships (CaBA) for landscape-wide consideration of nitrogen input, with regulation of nutrient management on surrounding farms, will enhance the management of catchments with shared responsibility and strengthen collaboration in parts of the country where less progress has been made.
Collaboration between catchment bodies and overlapping local councils would allow consideration of the cumulative catchment-wide pollution caused by intensive livestock units and wastewater treatment in their entirety by providing a more effective approach rather than, for example, addressing any impacts from a single livestock farm.
To effectively manage nitrogen at a national and a landscape level requires farmers to manage their nitrogen applications below a certain threshold. While nutrient management planning is currently a regulatory requirement by the Farming rules for water, farm-level nitrogen budgets would ensure these plans are implemented.
Imported Food and Feed
The Nitrogen Balance Sheet demonstrates that a significant driver of nitrogen pollution is the embedded nitrogen imported through food and feed for livestock.
Action is required to make diets healthier and more sustainable, enabling the public to have better procurement of healthy and sustainable foods. Public procurement shapes what ‘good food’ looks like and channels money to the right producers, therefore hospitals and schools should be supported in providing less but better meat as well as including alternative sources of protein in meals.
Reducing Emissions From Combustion Sources
As was outlined in the Net Zero Strategy, the Government should publish a plan with targets for making significant reductions in nitrous oxide emissions, for example through encouraging a reduction in inorganic fertiliser production and application.
An immediate halt on the expansion of fossil fuel production is necessary to meet Net Zero targets, with a ramping up of renewable energy. The Government should also revert the policies introduced over the summer 2023. These include:
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The exemption of 20% of households from the 2035 phase-out for fossil boilers.
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The delay of the fossil car phase-out date to 2035.
Land Management
Agroecological farming uses ecological principles to create environmentally sustainable and climate resilient agroecosystems, which work with biodiversity and enhance ecosystem services while contributing to nature recovery and a stable climate that our food security depends upon. Examples of agroecological systems include Organic, regenerative and conservation agriculture. While they all demonstrate varying environmental and social benefits, they typically recycle available nutrients or the use of nature-based inputs to provide fertility.
Agroecological farming practices minimise synthetic fossil-fuel based inputs, in addition to using what nature provides to provide fertility and build soil organic matter. Avoiding fossil-fuel based inputs means the farming system produces fewer greenhouse gases, is less damaging to biodiversity and human health, and improves farmers’ profit margins.
Click here to read more about farming at the sweet spot:
https://www.wildlifetrusts.org/sites/default/files/2023-06/Farming%20at%20the%20Sweet%20Spot_1.pdf
However, both agroecological and conventional farming systems should prioritise greater nitrogen use efficiency in their practice. Planning and applying only the amount of fertiliser that is required by the plant to grow will reduce the excess that is lost to the environment. As contextual variations in soil type, climate and cropping system impact nitrogen use efficiency, nutrient management plans should use SAP tests to measure the amount of nitrogen taken up by the plant.
Click here to read more about agroecological practices used in organic farming: https://www.soilassociation.org/farmers-growers/low-input-farming-advice/
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