Mikkelsen, M.H. Albrektsen, R. & Gyldenkærne, S. 2011: Danish emission inventories for agriculture. Inventories 1985 - 2009. National Environmental Research Institute, Aarhus University. 136 pp. – NERI Technical Report No. 810.
Regulations in international conventions oblige Denmark to prepare annual emission inventories and document the methodologies used to calculate emissions. The responsibility for preparing the emissions inventory for agriculture is in Denmark undertaken by the National Environmental Research Institute (NERI), Aarhus University. Chapter 2 contains a description of the emissions from the agricultural sector from 1985 to 2009. This report is an updated version of NERI Research Notes no. 231 published in 2006. The following chapters of the report include a detailed description of methods and data used to calculate the emissions.
The emissions from the agricultural sector include the greenhouse gases: methane (CH4) and nitrous oxide (N2O) as well as the air pollutants: ammonia (NH3), particulate matter (PM), non-methane volatile organic compounds (NMVOC) and other pollutants specifically related to the field burning of agricultural residues such as Nitrogen oxide (NOx), Carbon dioxide (CO2), Carbonmonoxid (CO), Sulphur dioxide (SO2), heavy metals, dioxin and PAH.
The emission calculation is based on an Integrated Database model for Agricultural emissions (IDA). The model covers all aspects of the agricultural inputs and estimates both greenhouse gases and air pollutants. The largest contribution to agricultural emissions originates from livestock production and most of the input data are sourced from Statistics Denmark and from the Faculty of Agricultural Sciences, Aarhus University. These data cover, e.g., the extent of the livestock production, land use, Danish standards for feed consumption and excretion. Furthermore, the estimation of nitrogen from leaching and runoff is based on data collected in connection with the Danish Action Plans for the Aquatic Environment. The emission inventory reflects the actual conditions for the Danish agricultural production. In cases where no Danish data are available, default values recommended by the Intergovernmental Panel on Climate Change (IPCC) and the European Monitoring and Evaluation Programme (EMEP) are used.
Approximately 97 % of the total NH3 emission originates from the agricultural sector as does approximately 16 % of total greenhouse gas emission.
The NH3 emission from 1985 to 2009 has decreased from 98 300 tonnes of NH3-N to 60 800 tonnes NH3-N, corresponding to a reduction of approximately 38 %. Converted to NH3, the 2009 emission is an estimated 73 800 tonnes NH3. Most of this NH3 emission is related to livestock manure and of this the emission from pigs and cattle contributed, respectively with, 44 % and 36 %.
The emission of greenhouse gases in 2009 is estimated at 9.6 million tonnes CO2 equivalents, a reduction of 25 % from the 1985 figure of 12.9 million tonnes CO2 equivalents and a reduction of 22 % since 1990, which is the base year of the Kyoto protocol.
The emission of CH4 is primarily related to cattle and pig production, which contributed 75 % and 20 % to the agricultural greenhouse gas emissions, respectively. The CH4 emission in 2009 is estimated to 195 gigagram (Gg), or given in CO2 equivalents as 4.1 million tonnes.
The emission of N2O primarily originates from transformation of nitrogen compounds in agricultural fields. The main sources are related to the use of livestock manure, synthetic fertiliser and nitrogen leaching and run-off. The emission of N2O in 2009 is estimated at 17.9 Gg, corresponding to 5.6 million tonnes CO2 equivalents.
Biogas plants that process animal slurry reduce the emission of CH4 and N2O. A methodology to estimate the emission reductions are not yet provided in the IPCC guidelines. The calculation of a lower emission from biogas treated slurry is based on the amount of treated slurry and the content of volatile solids and nitrogen. In 2009 approximately 8 % of all slurry was treated in biogas plants and the lower emission of greenhouse gases as a consequence of biogas treated slurry has result in a lower emission of 0.04 million tonnes CO2 equivalents.
Improvements in feed efficiency, use of low emission technologies, the utilisation of nitrogen in livestock manure and a significant decrease in the consumption of synthetic fertiliser are the most important explanations for the reduction of NH3. This development has furthermore resulted in a significant reduction of N2O emission, which is the main reason for a considerable fall in the total greenhouse gas. There has been a fall in CH4 emissions as a consequence of a reduction in the number of cattle. However, this trend is partially counteracted by changes in animal housing towards more slurry-based systems.
Full report in PDF-format (4,30 MB).
