Claim: Global warming disappearing oxygen from oceans

Dunno. The Earth is a big place. Lots of ocean coverage. Fifty years covers a lot of space-time. But the data coverage of this study looks pretty sparse.

Here are the reported results:

Here’s the data coverage from the study. Sure looks unsystematic.

The media release and abstract are below.

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Global ocean de-oxygenation quantified
The first in-depth study on the observed global ocean oxygen content was just published by Kiel scientists in Nature

HELMHOLTZ CENTRE FOR OCEAN RESEARCH KIEL (GEOMAR)

Oxygen is an essential necessity of life on land. The same applies for almost all organisms in the ocean. However, the oxygen supply in the oceans is threatened by global warming in two ways: Warmer surface waters take up less oxygen than colder waters. In addition, warmer water stabilizes the stratification of the ocean. This weakens the circulation connecting the surface with the deep ocean and less oxygen is transported into the deep sea. Therefore, many models predict a decrease in global oceanic oxygen inventory of the oceans due to global warming. The first global evaluation of millions of oxygen measurements seems to confirm this trend and points to first impacts of global change.

In the renowned scientific journal Nature the oceanographers Dr. Sunke Schmidtko, Dr. Lothar Stramma and Prof. Dr. Martin Visbeck from GEOMAR Helmholtz Centre for Ocean Research Kiel just published the most comprehensive study on global oxygen content in the world’s oceans so far. It demonstrates that the ocean’s oxygen content has decreased by more than two percent over the last 50 years. “Since large fishes in particular avoid or do not survive in areas with low oxygen content, these changes can have far-reaching biological consequences,” says Dr. Schmidtko, the lead-author of the study.

The researchers used all historic oxygen data available around the world for their work, supplemented it with current measurements and refined the interpolation procedures to more accurately reconstruct the development of the oxygen budget over the past 50 years. In some areas previous research had already shown a decrease in oxygen. “To quantify trends for the entire ocean, however, was more difficult since oxygen data from remote regions and the deep ocean is sparse,” explains Dr. Schmidtko, “we were able to document the oxygen distribution and its changes for the entire ocean for the first time. These numbers are an essential prerequisite for improving forecasts for the ocean of the future.”

The study also shows that, with the exception of a few regions, the oxygen content decreased throughout the entire ocean during the period investigated. The greatest loss was found in the North Pacific. “While the slight decrease of oxygen in the atmosphere is currently considered non-critical, the oxygen losses in the ocean can have far-reaching consequences because of the uneven distribution. For fisheries and coastal economies this process may have detrimental consequences,” emphasizes the co-author Dr. Lothar Stramma.

“However, with measurements alone, we cannot explain all the causes,” adds Professor Martin Visbeck, “natural processes occurring on time scales of a few decades may also have contributed to the observed decrease.” However, the results of the research are consistent with most model calculations that predict a further decrease in oxygen in the oceans due to higher atmospheric carbon dioxide concentrations and consequently higher global temperatures.

The new study is an important result for the ongoing work in the Collaborative Research Center (SFB) 754 funded by the German Research Foundation (DFG) at the Kiel University and GEOMAR. The SFB 754’s aim is to better understand the interaction between climate and biogeochemistry of the tropical ocean. “From the beginning of March onwards, four expeditions aboard the German research vessel METEOR will investigate the tropical oxygen minimum zone in the eastern Pacific off Peru. We hope to obtain further data on regional development which will also help us to better understand the global trends,” emphasizes Dr. Stramma, the expedition coordinator for the SFB.

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11 thoughts on “Claim: Global warming disappearing oxygen from oceans”

  1. “the ocean’s oxygen content has decreased by more than two percent over the last 50 years”
    What error is associated with your 2% estimate? Because error is multiplicative and you derived your estimate from empirical data and modeled data with some futzing on your part, the error must be astronomical.

  2. I am so over these people – how do they think we got safely to this point in time. One minute they are bleating about high CO2 levels and are now bleating about low oxygen levels – anyone who knows what they are talking about will tell you that CO2 is the secret of all oxygen production on earth. Oxygen is produced through the process of photosynthesis – more CO2 leads to a higher production of plant material and that to producing higher rates of oxygen – therefore the chicken and egg problem is solved in this case that without plants we die from lack of oxygen – most of the above text is what most of us call ‘best guess’ science.

  3. It’s well established that the phytoplankton population has increased by an order of magnitude. If there is an oxygen drop, it’s because there is more non-photosynthesizing organisms that feed of the phytoplankton. Nothing to see here, folks.

  4. warm liquids hold less dissolved gas than cold liquids. duh.
    around 1850 (more or less) we came out of the Little Ice Age.
    not the ice age means warmer temps, duh.

    we are still at least one full degree C less than the Roman Warm Period and yet people across the planet did not expire for lack of oxygen and fishing was just fine back then.

  5. If you were a bureaucratic scientist and paid a lot to produce bureaucrap and had no conscience would you too not write any old rubbish to justify your payday?!!

  6. Their claim that they measured “the entire ocean” is just ridiculous.

    When the plane went down over the Indian Ocean last year, it took months to find anything, even after a massive search. The scientists assisting the search admitted that we know more about the surface of the moon that we do about the oceans. But these guys say they measured the entire oceans of the world!

    Did they measure the ocean where the Russian ships and icebreakers are stuck in ice for the winter? My guess is no – they only measure a few places with warm water and let their computer models extrapolate whatever they want from there.

  7. There is so much corruption in big climate that there is every reason to believe the report contains much of what can be diplomatically called “dubious” procedures, data, methods and conclusions.

  8. Read the conclusion and it is clearly what I suspected: dubious at best.
    -O2 levels fluctuate naturally more than what they claim will occur in the future.
    – It takes a *lot* more warming (projected into the distant future, of course) to get O2 to move out like their models predict
    – This also means there will be smaller pH changes, since CO2 would be driven out by the same heating that drives out O2
    – The study of course disregards the biomass impact on the oceans

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