Big news: The ocean carbon sink is saturating

The long-feared saturation of one the world’s primary carbon sinks has apparently started. The BBC reports, “The amount of carbon dioxide being absorbed by the world’s oceans has reduced.”

After 10 years and more than 90,000 ship-based measurements of CO2 absorption, University of East Anglia researchers reached this stunning conclusion:

CO2 uptake halved between the mid-90s and 2000 to 2005.

The BBC writes: “Scientists believe global warming might get worse if the oceans soak up less of the greenhouse gas.”

Sigh. Note to the BBC, you don’t need a double hedge: If you’re going to just say “might get worse” you surely can drop “Scientists believe.” Frankly I doubt you can find many, if any, reputable scientists — or even the few remaining deniers — who would say that if the ocean sink saturates, global warming won’t get worse. I would probably phrase it this way: Global warming will accelerate if the oceans soak up less of the greenhouse gas.

The researchers say, “it is a tremendous surprise and very worrying because there were grounds for believing that in time the ocean might become ‘saturated’ with our emissions – unable to soak up any more.”

Why is that bad news?

Of all the CO2 emitted into the atmosphere, only half of it stays there; the rest goes into carbon sinks.

There are two major natural carbon sinks: the oceans and the land “biosphere”. They are equivalent in size, each absorbing a quarter of all CO2 emissions.

If the oceans stop taking up CO2, the atmosphere will inevitably take up more, accelerating global warming.

One question to readers: the BBC says this work is “published in a paper for the Journal of Geophysical Research.” I can’t find the paper online. If anyone finds a link, please send it to me, and I’ll excerpt and post it.

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3 Responses to Big news: The ocean carbon sink is saturating

  1. Jim Prall says:

    Our Univ. library gets the JGR so I was able to look. The JGR has four lettered sub-journals; part C covers oceans:
    I found this article under “in press” at that journal page. I believe it’s this one:
    Schuster, U., and A. J. Watson (2007), A variable and decreasing sink for atmospheric CO2 in the North Atlantic, J. Geophys. Res., doi:10.1029/2006JC003941, in press.
    [PDF] (accepted 24 July 2007)
    The in-press article PDF is at

    A time series of observations from merchant ships between the UK and the Caribbean is used to establish the variability of sea surface pCO2 and air-to-sea flux from the mid-
    1990s to early 2000s. We show that the sink for atmospheric CO2 exhibits important inter-annual variability, which is in phase across large regions from year to year.
    Additionally, there has been an inter-decadal decline, evident throughout the study region but especially significant in the northeast of the area covered, with the sink reducing
    >50% from the mid-nineties to the period 2002-2005. A review of available observations suggests a large region of decrease covering much of the North Atlantic but excluding the
    western subtropical areas. We estimate that the uptake of the region between 20o and 65oN declined by ~0.24 Pg C yr-1 from 1994/1995 to 2002-2005. Declining rates of
    winter-time mixing and ventilation between surface and subsurface waters due to increasing stratification, linked to variation in the North Atlantic Oscillation, are
    suggested as the main cause of the change. These are exacerbated by a contribution from the changing buffer capacity of the ocean water, as the carbon content of surface waters

  2. Jay Alt says:

    Here is Prof Andrew Watson’s website.

    Going to his publications list-

    “A variable and decreasing sink for atmospheric CO2 in the North Atlantic ”

    a draft copy you can see without subscription is here:

  3. Shannon says:

    thanks for the info. hopefully the trees and plants will make of the lacking ocean.