Soil organic carbon
- Soil carbon stocks in the EU-27 are around 75 billion tonnes of carbon; around 50 % of which is located in Ireland, Finland, Sweden and the United Kingdom (because of the large area of peatlands in these countries).
- The largest emissions of CO2 from soils are due to conversion (drainage) of organic soils, and amount to 20–40 tonnes of CO2 per hectare per year. The most effective option to manage soil carbon in order to mitigate climate change is to preserve existing stocks in soils, and especially the large stocks in peat and other soils with a high content of organic carbon.
- On average, soils in Europe are most likely to be accumulating carbon. Soils under grassland and forests are a carbon sink (estimated up to 80 million tonnes of carbon per year) whereas soils under arable land are a smaller carbon source (estimated from 10–40 million tonnes of carbon per year).
- The effects of climate change on soil organic carbon and soil respiration are complex, and depend on distinct climatic and biotic drivers. However, they lack rigorous supporting datasets.
- Climate change is expected to have an impact on soil carbon in the long term, but changes in the short term will more likely be driven by land management practices and land use change
What is the trend in soil organic carbon in Europe?
Variations in topsoil organic carbon content across Europe
Note: The map shows the percentage of organic carbon content in the surface horizon of soils in Europe. The darker regions correspond to soils with high values of organic carbon. The darkest colours, especially in Estonia, Fennoscandinavia, Ireland and the United Kingdom, denote peatlands.
- European Soil Portal provided by Joint Research Centre (JRC)
- Corine Land Cover 2006 raster data provided by European Environment Agency (EEA)
Around 45 % of the mineral soils in Europe have low or very low organic carbon content (0–2 %) and 45 % have a medium content (2–6 %) [i]. Figure 1 shows that low levels are particularly evident in southern Europe where 74 % of the land is covered by soils that have less than 2 % of organic carbon in the topsoil (0–30 cm) [ii]. However, areas of low organic carbon can be found almost everywhere, including in some parts of more northern countries such as Belgium, France, Germany, Norway and the United Kingdom. More than 50 % of EU soil organic carbon stocks are to be found in peatlands [iii].
In general, most soils across Europe are likely to be accumulating carbon. Except under drainage conditions, grassland soils accumulate carbon, although there is a high uncertainty as to the rate. Croplands generally act as a carbon source, although existing estimates are varied. Forest soils generally accumulate carbon (estimates range from 17 to 39 million tonnes per year [iv]).
However, estimates of European CO2, CH4 and N2O fluxes between 2000 and 2005, using both top-down estimates based on atmospheric observations and bottom-up estimates derived from ground-based measurements, suggest that CH4 emissions from livestock and N2O emissions from arable agriculture are fully compensated by the CO2 sink provided by forests and grasslands [v].
Soil organic carbon levels are determined mainly by the balance between net primary production (NPP) from vegetation and the rate of decomposition of the organic material. While climate change is expected to have an impact on soil carbon in the long term, changes in the short term will more likely be driven by land management practices and land-use change, which can mask the evidence of climate change impact on soil carbon stocks. The effects of climate change on soil are complex and lack rigorous supporting datasets.
[i] G. Louwagie, S. H. Gay, and A. Burrell, Final report on the project ‘Sustainable Agriculture and Soil Conservation (SoCo)’ JRC Scientific and Technical Reports (Luxembourg: European Commission, Joint Research Centre, 2009).
[ii] P. Zdruli, R.J.A. Jones, and L. Montanarella, Organic Matter in the Soils of Southern Europe European Soil Bureau Technical Report. (Luxembourg: Publications Office of the European Union, 2004).
[iii] R. Schils et al., Final report on review of existing information on the interrelations between soil and climate change (Climsoil). Final Report for the European Commission’s Directorate-General for the Environment (Brussels: European Commission, 2008).
[iv] Schils et al., Final report on review of existing information on the interrelations between soil and climate change (Climsoil). Final Report for the European Commission’s Directorate-General for the Environment.
[v] E.D. Schulze et al., „Importance of methane and nitrous oxide for Europe’s terrestrial greenhouse-gas balance“, Nature Geoscience 2 (2009): 842–850, doi:10.1038/ngeo686.
Indicator specification and metadata
- Variations in topsoil organic carbon content across Europe
- Carbon content [%]
Policy context and targets
In April 2013 the European Commission presented the EU Adaptation Strategy Package (http://ec.europa.eu/clima/policies/adaptation/what/documentation_en.htm). This package consists of the EU Strategy on adaptation to climate change /* COM/2013/0216 final */ and a number of supporting documents. One of the objectives of the EU Adaptation Strategy is Better informed decision-making, which should occur through Bridging the knowledge gap and Further developing Climate-ADAPT as the ‘one-stop shop’ for adaptation information in Europe. Further objectives include Promoting action by Member States and Climate-proofing EU action: promoting adaptation in key vulnerable sectors. Many EU Member States have already taken action, such as by adopting national adaptation strategies, and several have also prepared action plans on climate change adaptation.
The European Commission and the European Environment Agency have developed the European Climate Adaptation Platform (Climate-ADAPT, http://climate-adapt.eea.europa.eu/) to share knowledge on observed and projected climate change and its impacts on environmental and social systems and on human health; on relevant research; on EU, national and subnational adaptation strategies and plans; and on adaptation case studies.
No targets have been specified.
Related policy documents
Climate-ADAPT: Mainstreaming adaptation in EU sector policies
Overview of EU sector policies in which mainstreaming of adaptation to climate change is ongoing or explored
Climate-ADAPT: National adaptation strategies
Overview of activities of EEA member countries in preparing, developing and implementing adaptation strategies
DG CLIMA: Adaptation to climate change
Adaptation means anticipating the adverse effects of climate change and taking appropriate action to prevent or minimise the damage they can cause, or taking advantage of opportunities that may arise. It has been shown that well planned, early adaptation action saves money and lives later. This webportal provides information on all adaptation activities of the European Commission.
EU Adaptation Strategy Package
In April 2013 the European Commission adopted an EU strategy on adaptation to climate change which has been welcomed by the EU Member States. The strategy aims to make Europe more climate-resilient. By taking a coherent approach and providing for improved coordination, it will enhance the preparedness and capacity of all governance levels to respond to the impacts of climate change.
Methodology for indicator calculation
Spatial data from the European Soil Database v2.0 (soil), Global Historical Climatology Network (http://www.ncdc.noaa.gov/oa/climate/ghcn-daily/) (climate), CORINE Land Cover 1990 and USGS Global Land Cover Characterization (http://edc2.usgs.gov/glcc/glcc.php) (land cover) is displayed.
Methodology for gap filling
- Jones et al. 2010: Soil Atlas of the Northern Circumpolar Region Jones, A., Stolbovoy, V., Tarnocai, C., Broll, G., Spaargaren, O. and Montanarella, L. (2010) Soil Atlas of the Northern Circumpolar Region, 144. Publications Office of the European Union, Luxembourg.
Data sets uncertainty
Quantitative information, from both observations and modelling, on the past trends and impacts of climate change on soil and the various related feedbacks, is very limited. For example, data have been collected in forest soil surveys (e.g. ICP Forests, BioSoil and FutMon projects), but issues with survey quality in different countries makes comparison between countries (and between surveys) difficult (Hiederer and Durrant, 2010). To date, assessments have relied mainly on local case studies that have analysed how soil reacts under changing climate in combination with evolving agricultural and forest practices. Thus, European-wide soil information to help policymakers identify appropriate adaptation measures is absent. There is an urgent need to establish harmonised monitoring networks to provide a better and more quantitative understanding of this system. Currently, EU-wide soil indicators are (partly) based on estimates and modelling studies, most of which have not yet been validated. Nevertheless, in absence of quantification, other evidences can indicate emerging risks. For example, shifting tree lines in mountainous regions as a consequence of climate change may indicate an extinction risk of local soil biota.
Finally, when documenting and modelling changes in soil indicators, it is not always feasible to track long-term changes (signal) given the significant short-term variations (noise) that may occur (e.g. seasonal variations of soil organic carbon due to land management). Therefore, detected changes cannot always be attributed to climate change effects, as climate is only one of the soil-forming factors. Human activity can be more determining, both in measured/modelled past trends (baseline), and if projections including all possible factors were to be made. The latter points towards the critical role of effective land use and management in mitigating and adapting to climate change.
Further information on uncertainties is provided in Section 1.7 of the EEA report on Climate change, impacts, and vulnerability in Europe 2012 (http://www.eea.europa.eu/publications/climate-impacts-and-vulnerability-2012/)
No uncertainty has been specified
European Soil Portal
provided by Joint Research Centre (JRC)
Climate change (Primary topic)
Typology: Descriptive indicator (Type A - What is happening to the environment and to humans?)
- CLIM 027
- LSI 005
Contacts and ownership
EEA Contact InfoGeertrui Veerle Erika Louwagie
EEA Management Plan2012 2.0.1 (note: EEA internal system)
Frequency of updates
For references, please go to www.eea.europa.eu/soer or scan the QR code.
This briefing is part of the EEA's report The European Environment - State and Outlook 2015. The EEA is an official agency of the EU, tasked with providing information on Europe's environment.
PDF generated on 02 Oct 2016, 01:10 AM