Is the airborne fraction of anthropogenic CO2 emissions increasing?
Article first published online: 7 NOV 2009
Copyright 2009 by the American Geophysical Union.
Geophysical Research Letters
Volume 36, Issue 21, November 2009
How to Cite
2009), Is the airborne fraction of anthropogenic CO2 emissions increasing? Geophys. Res. Lett., 36, L21710, doi:10.1029/2009GL040613.(
- Issue published online: 7 NOV 2009
- Article first published online: 7 NOV 2009
- Manuscript Accepted: 23 SEP 2009
- Manuscript Revised: 21 SEP 2009
- Manuscript Received: 18 AUG 2009
- carbon cycle;
- CO2 emissions;
- climate change
 Several recent studies have highlighted the possibility that the oceans and terrestrial ecosystems have started loosing part of their ability to sequester a large proportion of the anthropogenic CO2 emissions. This is an important claim, because so far only about 40% of those emissions have stayed in the atmosphere, which has prevented additional climate change. This study re-examines the available atmospheric CO2 and emissions data including their uncertainties. It is shown that with those uncertainties, the trend in the airborne fraction since 1850 has been 0.7 ± 1.4% per decade, i.e. close to and not significantly different from zero. The analysis further shows that the statistical model of a constant airborne fraction agrees best with the available data if emissions from land use change are scaled down to 82% or less of their original estimates. Despite the predictions of coupled climate-carbon cycle models, no trend in the airborne fraction can be found.