Fig. 3. Observation-based estimates of anthropogenic CO₂ uptake.

The black line is our standard case global ocean-atmosphere flux increased by −0.57 PgC Cyr⁻¹ to account for pre-industrial and Arctic fluxes as described in the text. The shading gives one and two standard deviations of estimates around this value, including the uncertainty in gas transfer rates as assessed by Woolf et al.²⁰. Red horizontal line and uncertainty is a recent estimate of the global inventory increase of anthropogenic carbon in the ocean between 1994 and 2007¹⁷. Dashed lines: two previous estimates of global uptake based on surface data: blue dashed line from Landschützer et al.⁸, red dashed line from Rödenbeck et al.¹⁰, both as quoted in Le Quéré et al.³¹. Both are increased by the pre-industrial flux correction and Landschützer et al.⁸ also increased by Arctic correction.