Carbon Slowly Strangling Ocean

May 9, 2017

This scares me more than arctic methane.

Climate Progress:

Depletion of dissolved oxygen in our oceans, which can cause dead zones, is occurring much faster than expected, a new study finds.

And by combining oxygen loss with ever-worsening ocean warming and acidification, humans are re-creating the conditions that led to the worst-ever extinction, which killed over 90 percent of marine life 252 million years ago.

Researchers at Georgia Institute of Technology reviewed ocean data going back to 1958 and “found that oxygen levels started dropping in the 1980s as ocean temperatures began to climb.”

Scientists have long predicted that as carbon pollution warms the globe, the amount of oxygen in our oceans would drop, since warmer water can’t hold as much dissolved gas as colder water. And, Georgia Tech researchers point out, falling oxygen levels have recently led to more frequent low-oxygen events that “killed or displaced populations of fish, crabs and many other organisms.”

But what is especially worrisome about this new research is how quickly it is happening. “The trend of oxygen falling is about two to three times faster than what we predicted from the decrease of solubility associated with the ocean warming,” said lead researcher Prof. Taka Ito. “This is most likely due to the changes in ocean circulation and mixing associated with the heating of the near-surface waters and melting of polar ice.”

Global warming drives ocean stratification — the separation of the ocean into relatively distinct layers. This in turn speeds up oxygen loss, as explained in this the video above.

Below, my interviews with paleo experts about Earth’s extinction history.

A 2011 study, “Rapid expansion of oceanic anoxia immediately before the end-Permian mass extinction,” found that rapid and widespread anoxia (absence of oxygen) preceded “the largest mass extinction in Earth history, with the demise of an estimated 90 percent of all marine species.”

As National Geographic reported in 2015, we’re already starting to see the impacts of anoxia. “The waters of the Pacific Northwest, starting in 2002, intermittently have gotten so low in oxygen that at times they’ve smothered sea cucumbers, sea stars, anemones, and Dungeness crabs,” the magazine reported.


22 Responses to “Carbon Slowly Strangling Ocean”

  1. vierotchka Says:

    I read a few articles about that and I am really scared. Not for myself, but for my children’s and grand-daughter’s generations and those generations that will follow, if any will still be alive.

  2. gasbuggy Says:

    “Faster than expected” is happening in many aspects of research in Anthropogenic Climate Disruption (ACD) effects. Most of the specialists don’t compare notes on such issues. Some groups are following all the synergistic effects, including Guy McPherson on his Nature Bats Last blog. Many agree that the human species may go extinct by 2030.

    We live in a world surrounded by those in a state of profound denial. Look around at all the youth and places under construction that are based upon approximately 30-year payback periods.

  3. Yeah. That both events are occuring at the same time, deoxyegnation AND arctic methane releases should be fracking terrifying then… the oceans are not well for sure. the “deadly trio” that has accompanied all other previous mass extinctions, ocean warming, acidification and deoxyenation is happening right now. Not good atal.

  4. Ron Voisin Says:

    So…what ever you do, don’t believe your lying eyes when the satellite images of Earth show a greening planet with all forms of life exploding into abundance.

  5. Reblogged this on The Most Revolutionary Act and commented:
    By combining oxygen loss with ever-worsening ocean warming and acidification, humans are re-creating the conditions that led to the worst-ever extinction, which killed over 90 percent of marine life 252 million years ago.

  6. rogerthesurf Says:

    I do not see any empirical evidence in your article which supports your assertions.

    I am interested in what you say and would like to look deeper.

    Please refer me to the academic studies and observations that will help me undertand your article completely.



    • skeptictmac57 Says:

      Follow the link in the article to the Georgia Tech site and they used this citation:

      CITATION: Takamitsu Ito, Shoshiro Minobe, Matthew C. Long and Curtis Deutsch, “Upper Ocean O2 trends: 1958-2015,” (Geophysical Research Letters, April 2017).

      The 2011 study hyperlink links to this:

      The National Geographic link references this study:

      and this study too:

      and this:

      and so on. Do your homework

    • giovannidaprocida Says:

      Roger- I followed the embedded link to the Georgia Tech press release, and there found a link to the recent paper on decreasing oxygen in the oceans- Ito et al, 2017 (accepted)

    • redskylite Says:


      I’m surprised that you request help with studies on oxygen depletion here. This is a site where many participants are concerned with the world around us and the science of the effect of returning ancient carbon stocks to the waters and air, but it is not an academic study aid. Empirical evidence of previous episodes can be found from Paleontologists such as Peter Ward, and there are quite a few published works on the subject. Here is one from “Nature”, (peer reviewed with cross reference list), if you are genuinely interested in studying the phenomena. You can rent it for $5 or buy it outright for $32 – good reading to you.

      Decline in global oceanic oxygen content during the past five decades
      “Ocean models predict a decline in the dissolved oxygen inventory of the global ocean of one to seven per cent by the year 2100, caused by a combination of a warming-induced decline in oxygen solubility and reduced ventilation of the deep ocean. It is thought that such a decline in the oceanic oxygen content could affect ocean nutrient cycles and the marine habitat, with potentially detrimental consequences for fisheries and coastal economies. Regional observational data indicate a continuous decrease in oceanic dissolved oxygen concentrations in most regions of the global ocean, with an increase reported in a few limited areas, varying by study. ”

    • Paul Howarth Says:

      Hi Roger, Read the article, find the reference to the source of the information it contains, in this case the source of the main assertion in the article is Georgia Tech, and there’s a conveniently provided link to this source, repeat as necessary (sometimes there won’t be a link just a reference so you’ll have to do some digging yourself) until you find a paper published in a respected peer reviewed academic journal. Surprised you don’t already know this process if you’ve the knowledge and background to understand the academic studies in the first place.


    Good news about climate change is especially rare in the Arctic. But now comes news that increases in one greenhouse gas—methane—lead to the dramatic decline of another. Research off the coast of Norway’s Svalbard archipelago suggests that where methane gas bubbles up from seafloor seeps, surface waters directly above absorb twice as much carbon dioxide (CO2) as surrounding waters. The findings suggest that methane seeps in isolated spots in the Arctic could lessen the impact of climate change.

    Pohlman and his team conclude that the same physical forces that are pushing the methane bubbles up are also pumping nutrient-rich cold waters from the sea bed to the surface, fertilizing phytoplankton blooms that soak up CO2, they write today in the Proceedings of the National Academy of Sciences.

    But Pohlman says one can’t count on the methane fertilizing effect being the same everywhere. Even in his study area, it’s apt to change with the seasons. He notes that his team’s data were collected in the constant sunlight of Arctic summer. During the dark polar night, photosynthesis would drop to nearly nothing, and methane emissions wouldn’t be offset by declining CO2.

    The Devil in the detail of course is that as the phytoplankton dies o0ff and sinks to the sea bed where it decays, that process depletes the Oxygen leading to anoxic conditions in the lower depths and also to the production of H2S by the ancient tiny critturs.
    All leading to the Canfield Ocean state (See under a Green Sky), a player in most extinction events

    • Sir Charles Says:

      Methane is a greenhouse gas which is up to 105 times as potent as CO2. The sciencemag article mentions a factor of 30 and the authors of the study are assuming just a factor of 8 which both are ridiculously low.

      • greenman3610 Says:

        I think the potency depends on how long a time frame you stretch out to compare methane/co2. Methane absorbs long waves more strongly, but degrades over a decade or so, while co2 remains much longer well mixed in the atmosphere – so the widely differing estimates are not as far out of synch as they appear.

        • Sir Charles Says:

          The use of a long timescale for Methane is not realistic, given that the global warming tipping point is approaching at a faster pace. And a factor of 8 is nothing but ridiculous.

      • I agree, I too considered their figures shall we say circumspect, the figure more currently being quoted is 80x as that 28x is a theoretical based on a particular volume decaying over a century.
        I consider that >100x (seen quoted as >120x ) as a more accurate figure as the concentration is increasing, not decaying.

        Also note the decay is dependant on availability of OH which is apparently falling

  8. stephengn1 Says:

    Citizens of the world; Get ready for more hydrogen sulfide

  9. Sir Charles Says:

    A new study suggests that Alaska, with its huge stretches of tundra and forest, may be shifting from a net sink, or storehouse, of carbon to a net source. The study focused on one possible cause: warmer temperatures that keep the Arctic tundra from freezing until later in the fall, allowing plant respiration and microbial decomposition — processes that release carbon dioxide — to continue longer.

    => Tundra May Be Shifting Alaska to Put Out More Carbon Than It Stores, Study Says

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