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News from the CCE
Source: Fotolia

Publication on Critical Limits for Acidification and Nutrient Nitrogen

Title: Critical Limits for Acidification and Nutrient Nitrogen
The Simple Mass Balance (SMB) model is the most widely used steady-state model under the Air Convention to estimate critical loads for nutrient nitrogen (eutrophication) and sulphur together with nitrogen (acidification). Within the SMB model, so-called critical limits define chemical threshold values to prevent harmful effects in the ecosystem. In this report, the currently used critical limits for terrestrial ecosystems were reviewed. Results will be used by the Coordination Centre for Effects (CCE) to review the Mapping Manual for calculating critical loads. 

Publication on internationally proposed CLvs for NH3

Title: Experimental and literature review of internationally proposed critical levels for ammonia to protect the vegetation
Vascular plants, mosses and lichens react sensitively to the exposure to air pollutants and pollution from ammonia (NH3). Critical concentration values for ammonia to protect vegetation (so-called critical levels) were defined for risk assessment in the Geneva Convention on Long-Range Transboundary Air Pollution (CLRTAP). The project was used to review the current scientific status of those impact thresholds. In addition, extensive experimental studies were carried out to test the sensitivity of numerous native vascular plant species to NH3. The focus here was on species protected under the Natura2000 legislation and common in habitats in Germany.

Recent Meeting

40th TF & 31st CCE Meeting of the ICP M&M - Oslo (N) 23 - 25 April 2024 (Agenda)

Final Report for the new Land Cover Map is available now

A new map product for calculating the critical loads for eutrophication and acidification of terrestrial ecosystems and for modelling air quality is available at the Coordination Centre for Effects (CCE). The spatial extent of the map has been expanded and now includes countries in Europe as well as the Caucasus and Central Asia. The new map products represent land cover in 217 EUNIS classes or 13 RCG classes. Based on an evaluation of the availability and suitability of different spatial data it was decided to 1) use CORINE Land Cover 2018 and Ecosystem Type Map v3.1 and apply transition rules towards EUNIS Level 1 and Level 2 for European countries covered by CORINE Land Cover Maps, 2) use Copernicus Global Land Cover Map and apply transition rules towards EUNIS Level 1 and Level 2 for European countries not-covered by CORINE Land Cover Maps, 3) use Global Potential Natural Vegetation (GPNV) maps and the Harmonized World Soil Database (HWSD) to further disaggregate Level 2 classes towards Level 3. More than 700,000 points from the European Vegetation Archive (EVA) classified at EUNIS Level 3 were provided by the expert system for automatic classification of European vegetation plots to EUNIS Level 3 habitats. The new map product (Gebhardt 2023) replaces the former harmonized land cover map (described in the CCE Status Report 2009 by Slootweg, Posch, and Warrink 2009).

CCE Status Report 2022

The status report 2022 describes main CCE activities since the Centre was transferred to the German Environment Agency (UBA) in 2018. These activities include the following major projects:

i) Coordination of a revision process of empirical Critical Load for nitrogen (CLempN) in Europe resulting in scientifically adjusted CLempN ranges (Bobbink et al., 2022);

ii) Call for national data on Critical Load which yielded updated national Critical Load maps representing a respective spatial coverage of 40% for eutrophication and 45% for acidification of the model domain;

iii) Update of the European background database for Critical Load calculation, which was necessary in order to ensure a frictionless transfer of data and knowledge from RIVM to UBA. A comparison of Critical Load data between old and new database revealed only minor quantitative differences related to changes in input parameters to the simple mass balance (SMB) model for calculating Critical Load (Reinds et al., 2021);

iv) Assessment of Critical Load exceedances, which were calculated from Critical Load values of national data, the updated European Critical Load background database and modelled historic and projected deposition values provided by the EMEP Meteorological Synthesizing Center (MSC) West depending on past emissions and emission scenarios for 2030 - 2050 respectively. Calculated exceedances of Critical Load in the investigated years 2000 - 2020 occurred in a relatively large area of around 74% - 61% (decreasing trend from 2000 - 2020) of the model domain for eutrophication and a smaller area of 14% - 4% for acidification. Projections of Critical Load exceedances for the years 2030 to 2050 as a function of multiple emission scenarios highlighted ecosystem risks for eutrophication even under low emission scenarios;

v) Estimation of exceedance of critical atmospheric nitrogen inputs to the Baltic sea as a first attempt to evaluate the risk of open sea eutrophication.


The CCE aims at establishing a more dynamic communication within the WGE, and especially with its NFCs. Togehter with the TF Modelling & Mapping and the Centre for Dynamic Modelling (CDM) we plan to publish a newsletter at least twice a year. Please, feel free to submit information relevant for the whole group so we can include it into our next newsletter.

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