The oceanic sink for anthropogenic CO 2 from 1994 to 2007.

We quantify the oceanic sink for anthropogenic carbon dioxide (CO ₂ ) over the period 1994 to 2007 by using observations from the global repeat hydrography program and contrasting them to observations from the 1990s. Using a linear regression-based method, we find a global increase in the anthropogenic CO ₂ inventory of 34 ± 4 petagrams of carbon (Pg C) between 1994 and 2007. This is equivalent to an average uptake rate of 2.6 ± 0.3 Pg C year ^-1 and represents 31 ± 4% of the global anthropogenic CO ₂ emissions over this period. Although this global ocean sink estimate is consistent with the expectation of the ocean uptake having increased in proportion to the rise in atmospheric CO ₂ , substantial regional differences in storage rate are found, likely owing to climate variability-driven changes in ocean circulation.
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