Airborne fraction

The global carbon dioxide partitioning (atmospheric CO2, land sink, and ocean sink) averaged over the historical period (1900–2020)

The airborne fraction is a scaling factor defined as the ratio of the annual increase in atmospheric CO
2 to the CO
2 emissions from human sources.[1] It represents the proportion of human emitted CO2 that remains in the atmosphere. Observations over the past six decades show that the airborne fraction has remained relatively stable at around 45%.[2] This indicates that the land and ocean's capacity to absorb CO2 has kept up with the rise in human CO2 emissions, despite the occurrence of notable interannual and sub-decadal variability, which is predominantly driven by the land's ability to absorb CO2. There is some evidence for a recent increase in airborne fraction, which would imply a faster increase in atmospheric CO
2 for a given rate of human fossil-fuel burning.[3] Changes in carbon sinks can affect the airborne fraction as well.

  1. ^ Forster, P, V Ramaswamy, P Artaxo, et al. (2007) Changes in Atmospheric Constituents and in Radiative Forcing. In: Climate Change 2007: The Physical Science Basis. Contribution of Working Group I to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change [Solomon, S. et al. (eds.)]. Cambridge University Press, Cambridge, UK & New York, USA.[1]
  2. ^ Friedlingstein, Pierre; O'Sullivan, Michael; Jones, Matthew W.; Andrew, Robbie M.; Hauck, Judith; Olsen, Are; Peters, Glen P.; Peters, Wouter; Pongratz, Julia; Sitch, Stephen; Le Quéré, Corinne; Canadell, Josep G.; Ciais, Philippe; Jackson, Robert B.; Alin, Simone (2020). "Global Carbon Budget 2020". Earth System Science Data. 12 (4): 3269–3340. Bibcode:2020ESSD...12.3269F. doi:10.5194/essd-12-3269-2020. ISSN 1866-3516.
  3. ^ Canadell, Josep G.; Le Quéré, Corinne; Raupach, Michael R.; Field, Christopher B.; Buitenhuis, Erik T.; Ciais, Philippe; Conway, Thomas J.; Gillett, Nathan P.; Houghton, R. A.; Marland, Gregg (2007). "Contributions to accelerating atmospheric CO2 growth from economic activity, carbon intensity, and efficiency of natural sinks". Proceedings of the National Academy of Sciences of the United States of America. 104 (47): 18866–18870. doi:10.1073/pnas.0702737104. ISSN 1091-6490. PMC 2141868. PMID 17962418.