Scientists expect that the ocean will eventually absorb about 85% of anthropogenic C0₂ but because the ocean takes 1000 years to mix, this process will take many hundreds to thousands of years. An increasing sink is expected through 2100. It is because the increasing C0₂ in the atmosphere will drive more carbon into the ocean by the solubility mechanism. However, because of the chemistry of carbon in seawater, the ability of the ocean to absorb carbon decreases as the concentration increases. Anthropogenic forcings may slow down the large-scale overturning circulation of the ocean. As a result, they will reduce the efficiency of the ocean sink. Predictive models suggest significant regional changes in biological removal of carbon to the deep ocean, but a small net effect on globally-integrated ocean carbon uptake.

    Uncertainties in the ocean carbon uptake include the degree to ocean circulation. The ocean circulation will change with climate change and how this will modify carbon uptake. Model prediction suggest small future changes to the "biological pump" of carbon to the deep ocean. These models, however, do not account for potentially-important ecosystem shifts or for changes in carbon cycling in the near-surface ocean. Carbon cycling in coastal systems is poorly quantified. The carbon cycling includes estuaries and marshes, and the continental shelves. These are areas of active research.

    There are additional consequences to the ocean's uptake of carbon. C0₂ dissolves in seawater and forms carbonic acid. It eventually makes the ocean more acidic. From preindustrial times to present the pHof the ocean has declined 0,1 pH units, from 8.21 to 8.10, and it is likely to decline by another 0,-0.4 pH units by the 2100, assuming atmospheric C0₂ is about 800 ppmv by that time. Acidification will damage coral reefs. It likely places significant stress on species important to ocean food chain, as well, particularly in the Southern Ocean. Scientists are working hard to better-understand the impacts on organisms and the integrated effects on ocean ecosystems.

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(SOAL SBMPTN REFERENSI 2020)