All official European Union website addresses are in the europa.eu domain.
See all EU institutions and bodiesDo something for our planet, print this page only if needed. Even a small action can make an enormous difference when millions of people do it!
Indicator Assessment
Nitrogen emissions and deposition of nitrogen compounds have decreased since 1990 but relatively little compared to sulphur emissions. Agriculture and transport are the main sources of nitrogen pollution (EEA, 2007c). In addition, nitrogen components can lead to eutrophication of ecosystems. When this pollution exceeds certain levels ('critical load'), it is damaging to biodiversity. Critical load exceedance is still significant(1).
(1) The critical load of nutrient nitrogen is defined as 'the highest deposition of nitrogen as NOX and/or NHY below which harmful effects in ecosystem structure and function do not occur according to present knowledge' (ICP, M&M, 2004).
Exceedance of the critical loads for eutrophication in Europe (as average accumulated exceedances), 2004
Note: How to read the map: for Norway, exceedances of the critical load for nutrient nitrogen are in general not a major problem. Size of grid-cell: 50 km x 50 km.
CCE IMPACT Database MNP (Netherlands Environmental Assessment Agency); Coordination Centre for Effects (CCE), Data Centre of the International Cooperative Programme on Modelling and Mapping of Critical Levels and Loads and Air Pollution Effects, Risks and Trends (ICP Modelling and Mapping, ICP M&M), Convention on Long-range Transboundary Air Pollution (LRTAP) of the United Nations Economic Commission for Europe (UNECE) of the Convention on Long-range Transboundary Air Pollution. 2007.
CCE/EMEP, 2007. Personal communication, input to Air pollution in Europe 1990–2004. EEA Report No 2/2007. European Environment Agency, Copenhagen, Denmark. Available at: www.eea.europa.eu/publications/eea_report_2007_2.
CCE, 2007: 'Critical Loads of Nitrogen and Dynamic Modelling', Coordination Centre for Effects Progress Report 2007, MNP Report 500090001/2007.
Across the EU-25, approximately 47 % of (semi-) natural ecosystem areas were subject to nutrient nitrogen deposition leading to eutrophication in 2004. A relatively smaller 15 % of the ecosystem area received deposition of acidifying compounds including nitrogen (CCE/EMEP, 2007). Ecosystem types in use by European countries for critical load calculations are forests; marine and coastal habitats; littoral zones; mire, bog and fen habitats; grasslands and tall forb habitats; heathland, scrub and tundra habitats; inland un-vegetated or sparsely vegetated habitats; agricultural habitats; inland and surface water habitats (for details see CCE, 2007). The extent to which critical loads are exceeded varies significantly across Europe.
FURTHER INFORMATION
Exceedance of critical loads for nitrogen deposition indicating risks for biodiversity loss in (semi)-natural ecosystems.
%
eq ha-1 a-1
The availability of nutrients is one of the most important abiotic factors that determine plant species composition in ecosystems. Nitrogen is the limiting nutrient for plant growth in many natural and semi-natural ecosystems. Most of the plant species from oligotrophic and mesotrophic habitats are adapted to nutrient-poor conditions, and can only survive or compete successfully on soils with low nitrogen availability. High nitrogen deposition causes changes in vegetation composition and vegetation structure. These changes in turn affect the fauna composition (UNECE, 2003).
High variations in sensitivity to atmospheric nitrogen deposition have been observed between and within different natural and semi-natural ecosystems. Critical loads are used to describe this sensitivity. A critical load is defined as 'a quantitative estimate of an exposure to one or more pollutants below which significant harmful effects on specified sensitive elements of the environment do not occur according to present knowledge' (Nilsson and Grennfelt, 1988). Exceedances of critical loads by current or future nitrogen loads indicate risks for adverse effects on biodiversity.
Because of short- and long-range atmospheric transport, nitrogen (N) deposition has increased in many natural and semi-natural ecosystems across the world. The emissions of ammonia (NH3) and nitrogen oxides (NOX) strongly increased in Europe in the second half of the 20th century. Ammonia is volatilised from intensive agricultural systems, whereas nitrogen oxides originate mainly from burning of fossil fuel by traffic and industry (UNEP, 2005).
Significant geographical variability occurs in emissions and deposition of nitrogen compounds across Europe. Historically emission control strategies have focussed on reducing the emission of oxides of nitrogen. However across Europe it is now clear that nitrogen deposition is dominated by agricultural releases, predominantly ammonia. Therefore, while past effort has focussed predominately on reducing the oxides of nitrogen, future effort must also take into account reduced forms of nitrogen.
Excess nitrogen is one of the major threats to biodiversity. Excessive levels of reactive forms of nitrogen in the biosphere and atmosphere constitute a major threat to biodiversity in terrestrial, aquatic and coastal ecosystems. On land it causes loss of sensitive species and hence biodiversity by favouring a few nitrogen tolerant species over less tolerant ones. In coastal waters it leads to algal blooms and deoxygenated dead zones in which only a few bacteria may survive.
No targets have been specified
No related policy documents have been specified
Deposition loads are modelled as part of EMEP; on a European scale, the EMEP Unified Model is used (see http://www.emep.int/index_model.html). Monitoring of nitrogen deposition is used to calibrate the models.
European critical loads are assessed using scientifically reviewed methods and data.
There are various endpoints (protection aims) for setting critical loads. The ICP MandM and CCE have developed methods to derive critical loads for protecting (semi)-natural ecosystems (www.mnp.nl/cce):
1. Critical loads based on empirical data;
2. Critical loads based on dynamic ecosystem models;
3. Critical loads based on steady state modelling.
Methods 1 and 2 are particularly relevant for setting critical loads for protecting biodiversity.
Below are described the methodologies helping to produce the different maps/graphs relevant for this indicator.
(1) European maps of percentage natural area with critical load exceedances
(2) European maps of the percentage natural area protected under the EU Habitat directive With critical load exceedances
(3) European maps of the height of the exceedance in natural areas or protected areas
(4) Graphs of changes in percentage natural area with critical load exceedances or height of the exceedances
No methodology for gap filling has been specified. Probably this info has been added together with indicator calculation.
No methodology references available.
No uncertainty has been specified
No uncertainty has been specified
MAIN DISADVANTAGES OF THE INDICATOR
For references, please go to https://www.eea.europa.eu/data-and-maps/indicators/critical-load-exceedance-for-nitrogen/critical-load-exceedance-for-nitrogen or scan the QR code.
PDF generated on 28 Mar 2024, 06:04 PM
Engineered by: EEA Web Team
Software updated on 26 September 2023 08:13 from version 23.8.18
Software version: EEA Plone KGS 23.9.14
Document Actions
Share with others