Evil Oceans Produce 16 Times As Much CO2 As Humans

3 Comments on “Evil Oceans Produce 16 Times As Much CO2 As Humans”

  1. chaamjamal says:

    these natural flows have a high degree of uncertainty and the effect of fossil fuel emissions on the carbon cannot be detected in the context of these uncertainties

    Liked by 1 person

  2. chaamjamal says:

    on the carbon budget

    Liked by 2 people

  3. What is not covered by Dr Munshi’s note is the isotopic composition of the carbon in the carbon dioxide fluxes, a topic that Murry Salby touches upon in his text and elaborates further in the lectures uploaded to Youtube.

    Without suggesting anything specifically wrong in discussions of carbon isotope composition, I have not found the discussions of the isotopic composition of the outgassed CO2 to be satisfactory for reasons discussed towards the end of this comment.

    The key reasons are touched upon, but not elaborated, in Chapter 17 of Salby’s book. The ocean is the main sink for carbon derived from atmospheric CO2, about 40,000 Giga-tonnes. (tonne = 1000 kg = 2200 pounds) compared to annual flux of about 150 Gt. of which human emissions have been estimated as about 4%.

    As Dr Salby explains, there is seasonal absorption and outgassing of CO2 from the oceans driven by temperature changes. However, oceanic outgassing is mainly in the tropics and absorption is mainly in the polar regions.

    (Globally, the oceans account for 70% of the surface area. But between about 20 degrees north and 20 degrees south, the areas of land and ocean are roughly equal. Most land is in the NH and most ocean in the SH)

    Salby does not discuss the differences in the north and south polar regions as sinks. These differences arise from the greater annual range of temperatures in the northern hemisphere, the differing ratios of land and ocean, and the different rates of emissions of fossil fuels.

    (Though Salby’s book is 600+ pages, his text is essentially an introductory text for graduate students.)

    In my opinion, a key problem in relating the isotopic composition of the carbon in the CO2 to fossil fuel sources arises not solely from the fact that the flux is 25 times greater than fossil fuel emissions. The geographic separation of the sinks and sources of the oceanic CO2 flux seems to me to complicate the interpretation of the data.

    Geographic separation of the fluxes implies a time lag relates to the rate of movement of cold and warm oceanic currents, the thermohaline circulation. The Gulf Stream and othr currents may be mostly wind-driven and therefore higher speed.

    Overview: https://en.wikipedia.org/wiki/Thermohaline_circulation.

    In addition to meridional currents (latitudinal and longitudinal) there is vertical movement of water. Thus transit time varies non-linearly from multiple decades, to multiple centuries.

    CO2 in the oceans may not be well-mixed, at least not from the point of view of the isotope composition of the carbon. (And not as well-mixed as in the atmosphere.)

    This is because modern levels of fossil fuel emissions date from about 1950, a period of 65 years, while CO2 mixing in the world ocean seems to take much longer. If a substantial part of the CO2 produced since 1950 has sunk into the ocean, not much will have outgassed since then.

    How much of the current isotopic composition of atmospheric CO2 is a relic of the mediaval warm period?

    The oldest water is being upwelled in the north Pacific. How much of the CO2 being measured at Mona Loa is 1000 years old?

    The observed isotope composition of the atmosphere may be biased by a time lag longer than 65 years caused by geographic separation of oceanic CO2 sinks and outgassing.

    Global CO2 monitoring systems at the Earth’s surface may not alone be able to resolve this issue. However, there is some hope that data from the carbon monitoring satellite may add new information.

    There seem to be more questions than answers.


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