Accelerating atmospheric CO2

 

Although the paper I am about to discuss is a little dated (it was published in 2007) it still offers some very insightful information in regard to CO₂ and natural sinks.   The paper by Canadell et al (2007) was published by Proceeding of the National Academy of Science of the United States of America or PANS and was titled “Contributions to accelerating atmospheric CO2 growth from economic activity, carbon intensity, and efficiency of natural sinks”  It sets out to summarise the current (at the time) situation in regard to CO₂ increases in relation to three increases, two resulting from emissions and the third in relation to “increase in the airborne fraction (AF) of CO₂ emissions” (Canadell et al, 2007), which they say is evidence that natural carbon since, such as the ocean are becoming less efficient at sequestering anthropogenically produced emissions.  They find that AF observations are larger than initial model projection.     

Their findings, despite being now dated do make for an uncomfortable truth.  They found that from the start of the Industrial Revolution to 2006 CO₂ rose from 280 ppm to 381 ppm.  This they say is the highest it has been during the last 650,000 years (Canadell et al, 2007).  They also showed that emissions from 1850 to 2006 accounted for ≈ 330 PgC and that land use change added a further 158 PgC over this period.

Canadell et al (2007) also considered Gross World Product (GWP) in terms of carbon intensity, which is defined as  F_Foss/GWP, this is a ratio which “refers to  CO₂ emissions required to produce a unit of economic activity at a global scale” (Canadell et al, 2007) this value has been increasing by ≈ 3 % per year since 2000. 

They also looked at natural sinks and atmospheric growth rates of CO_2.  They state that anthropogenic emissions are exceeding sequester rates of natural skins (the worlds clean-up crew can’t keep pace with us).  AF (as discussed earlier) can vary greatly and since 1959 it was 0.0 to 0.8, but these rates have increased and from 2000 to 2006 AF was 0.45 (Canadell et al, 2007).  Canadell et al (2007) go on to say that since 1959, which saw the start of CO₂ monitoring, 2000 to 2007 have seen the most rapid increases in CO_2.

Table 1. Canadell et all (2007) produced this table to summaries the findings of their study in relations the global carbon budget.  Even just by glancing quickly at the ‘Sources’ column it is clear to see an increase from a total mean of 6.7 PgC y^-1  from 1959 to 2006 to a total of 9.1 PgC y^-1  from 2000 to 2006. 

 

Reference;

Canadell, J.G. Le Quéré, C. Raupach, M.R. Field, C.B. Buitenhuis, E.T. Ciais, P. Conway, T. J. Gillett, N.P. Houghton, R.A. Marland, G. (2007). Contributions to accelerating atmospheric CO2 growth from economic activity, carbon intensity, and efficiency of natural sinks. Proceeding of the National Academy of Science of the United States of America. 104, pp.18866–18870.