Biogeosciences www.biogeosciences.net 1726-4170 1726-4189 6 10 2009 10.5194/bg-6-2193-2009 http://www.biogeosciences.net/6/2193/2009/ http://www.biogeosciences.net/6/2193/2009/bg-6-2193-2009.html http://www.biogeosciences.net/6/2193/2009/bg-6-2193-2009.pdf 2193 2205 2009-10-15 An outlook on the Sub-Saharan Africa carbon balance A. Bombelli bombelli@unitus.it M. Henry S. Castaldi S. Adu-Bredu A. Arneth A. de Grandcourt E. Grieco W. L. Kutsch V. Lehsten A. Rasile M. Reichstein K. Tansey U. Weber R. Valentini Department of Forest Environment and Resources (DISAFRI), Univ. of Tuscia, via S. Camillo de Lellis, 01100 Viterbo, Italy Institut de Recherche pour le Développement, IRD, UR SeqBio, SupAgro, Bat. 12, 2 place Viala, 34060 Montpellier Cedex 1, France AgroParisTech-ENGREF, GEEFT, 648 rue Jean-François Breton, BP 7355 – 34086 Montpellier Cedex 4, France Dipartimento di Scienze Ambientali, Seconda Università di Napoli, via Vivaldi 43, 81100 Caserta, Italy Forestry Research Institute of Ghana (FORIG), P.O. Box 63 KNUST, Kumasi, Ghana Department of Physical Geography and Ecosystems Analysis (INES), Centre for GeoBiosphere Science, Lund University, Sölvegatan 12, 223 62, Lund, Sweden Centre de coopération Internationale en Recherche Agronomique pour le Développement (CIRAD), Persyst, UPR80, TA B-80/D, 34398 Montpellier Cedex 5, France Unité de recherche sur la productivité des plantations industrielles (UR2PI), BP 1291, Pointe Noire, Congo Max-Planck Institute for Biogeochemistry, Hans-Knöll Strasse 10, 07745 JENA, Germany Department of Geography, University of Leicester, Leicester, LE1 7RH, UK Euro-Mediterranean Centre for Climate Change (CMCC), via Augusto Imperatore 16, 73100 Lecce, Italy This study gives an outlook on the carbon balance of Sub-Saharan Africa (SSA) by presenting a summary of currently available results from the project CarboAfrica (namely net ecosystem productivity and emissions from fires, deforestation and forest degradation, by field and model estimates) supplemented by bibliographic data and compared with a new synthesis of the data from national communications to UNFCCC. According to these preliminary estimates the biogenic carbon balance of SSA varies from 0.16 Pg C y^−1 to a much higher sink of 1.00 Pg C y^−1 (depending on the source data). Models estimates would give an unrealistic sink of 3.23 Pg C y^−1, confirming their current inadequacy when applied to Africa. The carbon uptake by forests and savannas (0.34 and 1.89 Pg C y^−1, respectively,) are the main contributors to the resulting sink. Fires (0.72 Pg C y^−1) and deforestation (0.25 Pg C y^−1) are the main contributors to the SSA carbon emissions, while the agricultural sector and forest degradation contributes only with 0.12 and 0.08 Pg C y^−1, respectively. Savannas play a major role in shaping the SSA carbon balance, due to their large extension, their fire regime, and their strong interannual NEP variability, but they are also a major uncertainty in the overall budget. 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