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The European carbon balance. Part 4: integration of carbon and other trace‐gas fluxes

2010; Wiley; Volume: 16; Issue: 5 Linguagem: Inglês

10.1111/j.1365-2486.2010.02215.x

1365-2486

Ernst‐Detlef Schulze, Philippe Ciais, Sebastiaan Luyssaert, Marion Schrumpf, Ivan A. Janssens, Balendra Thiruchittampalam, J. Theloke, Mathieu Saurat, Stefan Bringezu, Jos Lelieveld, Annalea Lohila, Corinna Rebmann, Martin Jung, David Bastviken, Gwénaël Abril, Giacomo Grassi, Adrian Leip, Annette Freibauer, Werner L. Kutsch, Axel Don, Jens Nieschulze, Annett Börner, J. H. C. Gash, A. J. Dolman,

Soil Carbon and Nitrogen Dynamics

Abstract Overviewing the European carbon (C), greenhouse gas (GHG), and non‐GHG fluxes, gross primary productivity (GPP) is about 9.3 Pg yr −1 , and fossil fuel imports are 1.6 Pg yr −1 . GPP is about 1.25% of solar radiation, containing about 360 × 10 18 J energy – five times the energy content of annual fossil fuel use. Net primary production (NPP) is 50%, terrestrial net biome productivity, NBP, 3%, and the net GHG balance, NGB, 0.3% of GPP. Human harvest uses 20% of NPP or 10% of GPP, or alternatively 1‰ of solar radiation after accounting for the inherent cost of agriculture and forestry, for production of pesticides and fertilizer, the return of organic fertilizer, and for the C equivalent cost of GHG emissions. C equivalents are defined on a global warming potential with a 100‐year time horizon. The equivalent of about 2.4% of the mineral fertilizer input is emitted as N 2 O. Agricultural emissions to the atmosphere are about 40% of total methane, 60% of total NO‐N, 70% of total N 2 O‐N, and 95% of total NH 3 ‐N emissions of Europe. European soils are a net C sink (114 Tg yr −1 ), but considering the emissions of GHGs, soils are a source of about 26 Tg CO 2 C‐equivalent yr −1 . Forest, grassland and sediment C sinks are offset by GHG emissions from croplands, peatlands and inland waters. Non‐GHGs (NH 3 , NO x ) interact significantly with the GHG and the C cycle through ammonium nitrate aerosols and dry deposition. Wet deposition of nitrogen (N) supports about 50% of forest timber growth. Land use change is regionally important. The absolute flux values total about 50 Tg C yr −1 . Nevertheless, for the European trace‐gas balance, land‐use intensity is more important than land‐use change. This study shows that emissions of GHGs and non‐GHGs significantly distort the C cycle and eliminate apparent C sinks.