Reference
Schimel, D., Melillo, J., Tian, H., McGuire, A.D., Kicklighter, D., Kittel, T., Rosenbloom, N., Running, S., Thorton, P., Ojima, D., Parton, W., Kelly, R., Sykes, M., Neilson, R. and Rizzo, B. 2000. Contribution of increasing CO2 and climate to carbon storage by ecosystems in the United States. Science 287: 2004-2006.
What was done
The authors used three ecosystem models to simulate changes to soil and vegetative carbon fluxes in the United States for the period 1980-1993, as part of an extensive project designed to better understand how changes in climate and atmospheric CO2 concentration impact terrestrial carbon sequestration by influencing ecosystem physiological processes.
What was learned
Over the 13-year simulation period, the models calculated an average terrestrial carbon sink in the United States of 0.08 Pg carbon per year (1 Pg = 1015 g). By running the models at a constant atmospheric CO2 concentration, the authors determined that the bulk of this terrestrial carbon sink resulted from the CO2 fertilization effect brought about by the air's increasing CO2 content, with minor influences modulated by climate change.
What it means
As the CO2 concentration of the air continues to rise, it will likely stimulate the productivity of earth's vegetation, thus increasing the terrestrial carbon sink. Over time, a portion of the carbon sequestered in plant tissues will ultimately make its way into soils, thereby increasing soil organic carbon contents and the magnitude of belowground carbon storage.
Reviewed 15 June 2000