Impact of terrestrial biosphere carbon exchanges on the anomalous CO2 increase in 2002–2003
Article first published online: 5 MAY 2007
Copyright 2007 by the American Geophysical Union.
Geophysical Research Letters
Volume 34, Issue 9, May 2007
How to Cite
2007), Impact of terrestrial biosphere carbon exchanges on the anomalous CO2 increase in 2002–2003, Geophys. Res. Lett., 34, L09703, doi:10.1029/2006GL029019., , , , , and (
- Issue published online: 5 MAY 2007
- Article first published online: 5 MAY 2007
- Manuscript Accepted: 3 APR 2007
- Manuscript Revised: 20 FEB 2007
- Manuscript Received: 6 DEC 2006
- carbon cycle;
- climate change;
- terrestrial biosphere
 Understanding the carbon dynamics of the terrestrial biosphere during climate fluctuations is a prerequisite for any reliable modeling of the climate-carbon cycle feedback. We drive a terrestrial vegetation model with observed climate data to show that most of the fluctuations in atmospheric CO2 are consistent with the modeled shift in the balance between carbon uptake by terrestrial plants and carbon loss through soil and plant respiration. Simulated anomalies of the Fraction of Absorbed Photosynthetically Active Radiation (FAPAR) during the last two El Niño events also agree well with satellite observations. Our model results suggest that changes in net primary productivity (NPP) are mainly responsible for the observed anomalies in the atmospheric CO2 growth rate. Changes in heterotrophic respiration (Rh) mostly happen in the same direction, but with smaller amplitude. We attribute the unusual acceleration of the atmospheric CO2 growth rate during 2002–2003 to a coincidence of moderate El Niño conditions in the tropics with a strong NPP decrease at northern mid latitudes, only partially compensated by decreased Rh.