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| Titel |
A full greenhouse gases budget of Africa: synthesis, uncertainties, and vulnerabilities |
| VerfasserIn |
R. Valentini, A. Arneth, A. Bombelli, S. Castaldi, R. Cazzolla Gatti, F. Chevallier, P. Ciais, E. Grieco, J. Hartmann, M. Henry, R. A. Houghton, M. Jung, W. L. Kutsch, Y. Malhi, E. Mayorga, L. Merbold, G. Murray-Tortarolo, D. Papale, P. Peylin, B. Poulter, P. A. Raymond, M. Santini, S. Sitch, G. Vaglio Laurin, G. R. van der Werf, C. A. Williams, R. J. Scholes |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1726-4170
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| Digitales Dokument |
URL |
| Erschienen |
In: Biogeosciences ; 11, no. 2 ; Nr. 11, no. 2 (2014-01-28), S.381-407 |
| Datensatznummer |
250117149
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| Publikation (Nr.) |
 copernicus.org/bg-11-381-2014.pdf |
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| Zusammenfassung |
This paper, developed under the framework of the RECCAP initiative, aims at
providing improved estimates of the carbon and GHG (CO2, CH4 and
N2O) balance of continental Africa. The various components and processes
of the African carbon and GHG budget are considered, existing data reviewed,
and new data from different methodologies (inventories, ecosystem flux
measurements, models, and atmospheric inversions) presented. Uncertainties
are quantified and current gaps and weaknesses in knowledge and monitoring
systems described in order to guide future requirements. The majority of
results agree that Africa is a small sink of carbon on an annual scale, with
an average value of −0.61 ± 0.58 Pg C yr−1. Nevertheless, the
emissions of CH4 and N2O may turn Africa into a net source of
radiative forcing in CO2 equivalent terms. At sub-regional level, there
is significant spatial variability in both sources and sinks, due to the
diversity of biomes represented and differences in the degree of anthropic
impacts. Southern Africa is the main source region; while central Africa,
with its evergreen tropical forests, is the main sink. Emissions from land-use change in Africa are significant (around
0.32 ± 0.05 Pg C yr−1), even higher than the fossil fuel
emissions: this is a unique feature among all the continents. There could be
significant carbon losses from forest land even without deforestation,
resulting from the impact of selective logging. Fires play a significant role
in the African carbon cycle, with 1.03 ± 0.22 Pg C yr−1 of
carbon emissions, and 90% originating in savannas and dry woodlands. A
large portion of the wild fire emissions are compensated by CO2 uptake
during the growing season, but an uncertain fraction of the emission from
wood harvested for domestic use is not. Most of these fluxes have large
interannual variability, on the order of ±0.5 Pg C yr−1 in
standard deviation, accounting for around 25% of the year-to-year
variation in the global carbon budget.
Despite the high uncertainty, the estimates provided in this paper show the
important role that Africa plays in the global carbon cycle, both in terms
of absolute contribution, and as a key source of interannual variability. |
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