Articles | Volume 12, issue 18
https://doi.org/10.5194/bg-12-5291-2015
https://doi.org/10.5194/bg-12-5291-2015
Research article
 | 
16 Sep 2015
Research article |  | 16 Sep 2015

Derivation of greenhouse gas emission factors for peatlands managed for extraction in the Republic of Ireland and the United Kingdom

D. Wilson, S. D. Dixon, R. R. E. Artz, T. E. L. Smith, C. D. Evans, H. J. F. Owen, E. Archer, and F. Renou-Wilson

Abstract. Drained peatlands are significant hotspots of carbon dioxide (CO2) emissions and may also be more vulnerable to fire with its associated gaseous emissions. Under the United Nations Framework Convention on Climate Change (UNFCCC) and the Kyoto Protocol, greenhouse gas (GHG) emissions from peatlands managed for extraction are reported on an annual basis. However, the Tier 1 (default) emission factors (EFs) provided in the IPCC 2013 Wetlands Supplement for this land use category may not be representative in all cases and countries are encouraged to move to higher-tier reporting levels with reduced uncertainty levels based on country- or regional-specific data. In this study, we quantified (1) CO2-C emissions from nine peat extraction sites in the Republic of Ireland and the United Kingdom, which were initially disaggregated by land use type (industrial versus domestic peat extraction), and (2) a range of GHGs that are released to the atmosphere with the burning of peat. Drainage-related methane (CH4) and nitrous oxide (N2O) emissions as well as CO2-C emissions associated with the off-site decomposition of horticultural peat were not included here. Our results show that net CO2-C emissions were strongly controlled by soil temperature at the industrial sites (bare peat) and by soil temperature and leaf area index at the vegetated domestic sites. Our derived EFs of 1.70 (±0.47) and 1.64 (±0.44) t CO2-C ha−1 yr−1 for the industrial and domestic sites respectively are considerably lower than the Tier 1 EF (2.8 ± 1.7 t CO2-C ha−1 yr−1) provided in the Wetlands Supplement. We propose that the difference between our derived values and the Wetlands Supplement value is due to differences in peat quality and, consequently, decomposition rates. Emissions from burning of the peat (g kg−1 dry fuel burned) were estimated to be approximately 1346 CO2, 8.35 methane (CH4), 218 carbon monoxide (CO), 1.53 ethane (C2H6), 1.74 ethylene (C2H4), 0.60 methanol (CH3OH), 2.21 hydrogen cyanide (HCN) and 0.73 ammonia (NH3), and this emphasises the importance of understanding the full suite of trace gas emissions from biomass burning. Our results highlight the importance of generating reliable Tier 2 values for different regions and land use categories. Furthermore, given that the IPCC Tier 1 EF was only based on 20 sites (all from Canada and Fennoscandia), we suggest that data from another 9 sites significantly expand the global data set, as well as adding a new region.

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Short summary
We quantified carbon dioxide emissions from drained peat extraction sites in the Republic of Ireland and the United Kingdom and also measured a range of greenhouse gases that are released to the atmosphere with the burning of peat. Our derived carbon dioxide emission factors were considerably lower than those derived by the IPCC, which has major implications for National Inventory reporting under the United Nations Framework Convention on Climate Change (UNFCCC) and the Kyoto Protocol.
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