Graph of the Day: Anthropogenic Carbon Uptake Rate, 1765 – 2008

This graph shows the uptake history over the industrial era (ad 1765 to ad 2008) computed from the time-varying inventory. (The corresponding space- and time-varying change in surface disequilibrium of CO2 driving this uptake is also estimated by our inversion method.) There has been a sharp increase in ocean uptake since the 1950s in response to a higher growth rate of atmospheric CO2, although the rate of increase has decreased somewhat in the last few decades. Our estimated uptake rate for the 1990s, 2.0 ± 0.6 Pg C yr-1, agrees well with the IPCC consensus estimate based on independent methods4 (Fig. 2 and Table 1). The shaded area represents the error envelope (see Fig. 1 legend). Also shown are the decadal average uptake rates adopted by the IPCC fourth-assessment report (AR4)4 (blue circles; vertical error bars are ±1 s.d. and horizontal error bars span the averaging period of years) and the atmospheric CO2 mixing ratio29 used for the inversion (red dashed line).

S Khatiwala et al., Reconstruction of the history of anthropogenic CO2 concentrations in the ocean, Nature 462, 346-349 (2009) doi:10.1038/nature08526 Technorati claim token: 5TU663BK27SJ (from web) ZP2RFGNCBVTQ (from email)