Africa and the global carbon cycle
Christopher A Williams1, Niall P Hanan1, Jason C Neff2, Robert J Scholes3, Joseph A Berry4, A Scott Denning5 and David F Baker6
1Natural Resource Ecology Laboratory, Colorado State University, Fort Collins, CO 80523, USA
2University of Colorado, Boulder, CO 80309, USA
3Council for Scientific and Industrial Research, Pretoria 001, South Africa
4Carnegie Institution of Washington, Stanford, CA, 94305, USA
5Department of Atmospheric Sciences, Colorado State University, Fort Collins, CO 80523, USA
6National Center for Atmospheric Research, Terrestrial Science Section, Climate and Global Dynamics Division, 1850 Table Mesa Dr., Boulder, CO 80307, USA
The African continent has a large and growing role in the global carbon cycle, with potentially important climate change implications. However, the sparse observation network in and around the African continent means that Africa is one of the weakest links in our understanding of the global carbon cycle. Here, we combine data from regional and global inventories as well as forward and inverse model analyses to appraise what is known about Africa's continental-scale carbon dynamics. With low fossil emissions and productivity that largely compensates respiration, land conversion is Africa's primary net carbon release, much of it through burning of forests. Savanna fire emissions, though large, represent a short-term source that is offset by ensuing regrowth. While current data suggest a near zero decadal-scale carbon balance, interannual climate fluctuations (especially drought) induce sizeable variability in net ecosystem productivity and savanna fire emissions such that Africa is a major source of interannual variability in global atmospheric CO2. Considering the continent's sizeable carbon stocks, their seemingly high vulnerability to anticipated climate and land use change, as well as growing populations and industrialization, Africa's carbon emissions and their interannual variability are likely to undergo substantial increases through the 21st century.
Carbon Balance and Management 2007, 2:3. This is an Open Access article distributed under the terms of the Creative Commons Attribution License.