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This question already has an answer here:

In this report of a mathematical model (original paper here) about the response of ocean plankton to climate change, its author claims the following:

By 2100, the earth at sea level could have atmospheric oxygen levels comparable to the top of Mount Everest today. And as far as I know, people cannot normally stay on Everest without oxygen masks for more than a few minutes.

I'm not interested in whether his model about the oxygen production by plankton is correct or not, but is his claim that the consequence of this could be an immediate shortage of oxygen remotely credible? To put this another way, even if oxygen production in the ocean suffered a catastrophic decline, would we see oxygen shortages by 2100?

NB. This question was raised as the linked paper has now generated more than one question here (Will global warming reduce available oxygen? and Is space exploration even possible in an oxygen constrained Earth?). Neither of these question address the most outrageous claim in the news stories that global warming could lead to a ~70% reduction in the atmospheric oxygen by 2100 (the partial pressure of oxygen at the top of Everest is about 30% of its value at sea-level). One commenter on the original question even suggested that this, much more specific, question should be asked. So stop saying it is a duplicate: it is clearly a much more specific claim that is completely unaddressed in the answers to the other questions.

marked as duplicate by PoloHoleSet, Paul, Sklivvz May 12 '17 at 8:28

This question has been asked before and already has an answer. If those answers do not fully address your question, please ask a new question.

  • To the potential answerers: please review our theoretical answer and original research policies on meta before answering. Answers which ignore our theoretical answer/original research policies will be deleted. – Sklivvz May 12 '17 at 0:19
  • I don't really understand the difference between this question and the dupe: I understand the other does not ask specifically about the 70% number, but neither does this. This makes me think that either this is a duplicate, or you need to clarify it. In either case, I'm putting it on hold because of this reason. – Sklivvz May 12 '17 at 8:30
  • @Sklivvz The original question asked whether the effects of warming could lead to a reduction in oxygen production. The answers address whether the modelling in the paper, specifically focussed on plankton, is plausible but it is hard to judge an esoteric paper here. The paper's author is quoted as making a much more remarkable claim about the speed and extent of oxygen reduction. The original question doesn't address those issues at all. – matt_black May 12 '17 at 8:40
  • @Sklivvz The claim in the quote specifically asks about himalayan levels of oxygen by 2100 (they are both in the quoted claim). So I'm not certain how you can claim the 70% isn't mentioned (or do I need to show that there is only around 30% of the sea-level oxygen at the top of Everest? I thought that was obvious.) – matt_black May 12 '17 at 8:44
  • The claim might imply that number, however your actual questions are not about that number. They should be about the paper (or the reporting of the paper), not about the future or duplicates of the other question!? :-D – Sklivvz May 12 '17 at 8:53
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Disconnect between journal article and the blog post on it

The sketchy claim investigated in this question is:

“By 2100, the earth at sea level could have atmospheric oxygen levels comparable to the top of Mount Everest today. And as far as I know, people cannot normally stay on Everest without oxygen masks for more than a few minutes,” Petrovskii said.

While this quote is attributed to the author of the journal article, this claim doesn't appear in the journal. Rather:

Note that it was not our aim here to calculate precise critical values of the oxygen production rate. Instead, our aim is to identify the new threat in principle rather than to link our analysis to specific plankton species or specific marine ecosystems.

This stress on "in principle" seems to reflect that the authors didn't want to actually claim that they believed this to be a threat.

Additionally, the journal stresses that they were reporting a model without even attempting to estimate the values for the parameters:

Similarly, we do not attempt to estimate the value of the model parameters.

Finally, they note that this model wasn't an attempt at realism:

In contrast to other simulation studies where complicated “realistic” marine ecosystem models were used (e.g., Chapelle et al. 2000; Fasham et al. 1990; Hull et al. 2008), our model is relatively simple.

Checking Google, the earliest found reference to the alleged quote comes from "Report: The World Will Run out of Breathable Air Unless Carbon Is Cut" (2015-12-03). This story reports the quote in relation to the article, but since it's not in the article, it's unclear how the reporters obtained it; they don't mention an interview or correspondence with the author.

So:

  • We're not sure if the journal article's author actually made this claim.

  • Even if the claim's real, it doesn't appear to be peer-reviewed.

  • The peer-reviewed journal article explicitly disclaims concrete claims and realism, stressing that they were only trying to demonstrate a concern "in principle".

  • As noted by the estimates above, the claim seems pretty implausible.

  • I don't think removing the references to the oxygen cycle and the known amount of oxygen stock and production make this better in any way. They are clear, reference able facts that cast serious doubt on the claim. – matt_black May 12 '17 at 8:47
  • @matt_black please review our theoretical answer policies before making inaccurate comments. The policies are there for a reason, there's no need to reopen that discussion yet again. – Sklivvz May 12 '17 at 9:25
  • Matt, please take further comments about the policy to Skeptics Chat or Skeptics Meta. – Sklivvz May 12 '17 at 9:28
  • @Sklivvz Done. Now a meta question wondering why good direct answers are being ruled as theoretical. I think we have very different ideas about what constitutes theory. – matt_black May 12 '17 at 13:34
  • The source I gave for the question has a direct quote from the principal author as the source of the claim. It looks like someone interviewed him and this is where the quote if from. – matt_black May 12 '17 at 21:33

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