David, The residence time of oxygen in the atmosphere + ocean + biosphere with respect to the lithosphere is millions of years.
There are about 4 x 10 ** 19 mol of O2 in the atmosphere. The rate of removal of this O2 by organic carbon weathering is about 4 x 10 ** 12 mol per year. I am not sure about pyrite oxidation and so on but you can check out the attached paper for an entree into the literature. In any case, the 1000 year number you cite is not based on any reliable literature value. A better guess might be that we would have breathable oxygen on the order of a million years if you eliminated all life on land and sea. If life were eliminated in the oceans only, I don't know of anything that would impede our ability to eat Chicken McNuggets and watch TV indefinitely. Let me make it clear that I value life in the oceans quite highly and do not at all like Chicken McNuggets. (For some reason, nutters on the web think that you can't discuss anything unless you are advocating actually doing it.) Best, Ken On Saturday, June 8, 2013, David Lewis wrote: > During the Q&A after his 2012 AGU talk entitled "*Ocean Acidification: > Adaptive Challenge or Extinction Threat?*", Ken Caldeira said: "I > actually think* if you sterilize the ocean*, yes vulnerable people would > be hurt, poor people would be hurt, but that* we'd still have Chicken > McNuggets and TV shows and basically we'd be OK* " A video of Ken's > entire talk is* available > here*<http://fallmeeting.agu.org/2012/events/gc44c-special-lecture-in-ocean-acidification-consequences-of-excess-carbon-dioxide-in-the-marine-environment-video-on-demand/>. > He lays out the McNugget/Ocean Sterilization hypothesis starting at *minute > 50:20*. > > This seemed to be Ken's answer to the question he posed in his subtitle, > i.e. is homo sapiens facing a threat of extinction as a result of any > particular odd behavior the species is engaged in at the moment such as > carelessly dumping waste gases into the atmosphere which are changing the > chemistry of the global ocean? > > Callum Roberts, a scientist who studies the impact of human activity on > marine ecosystems, addressed an audience at the University of Sydney this > year where he discussed the many problems human activity is causing life in > the oceans. He interrupted his litany of woe briefly to tell the audience > of some "*good news*" he had: "even if all the ocean's primary > productivity were shot down tomorrow,* it will still be a long time > before we suffocate *because there's plenty of oxygen in the atmosphere, > enough for more than 1,000 years. So hopefully we can get our heads around > a few problems before then". A transcript and audio download of Callum's > speech is* available > here<http://www.abc.net.au/radionational/programs/scienceshow/the-coming-crisis-for-the--oceans/4735314> > *. His "we've got 1,000 entire years" comment starts around *minute 39:30 > *. (Callum's Wikipedia page is > here<http://en.wikipedia.org/wiki/Callum_Roberts> > ). > > Callum does not address Ken's remarks directly. I happened to hear him > and thought this 1,000 year time limit idea could be a blow to those who > thought the McNugget deliveries would still be happening in 3013 or so. I > thought some of them might be hanging around here so I post this. > > A transcript of the relevant section of Ken's AGU talk follows: > > Around minute 50:20, Ken Caldeira answers a question from the audience: > "well this is a sort of deep type question - the question is, what if > reefs disappear, what does that mean, or to summarize... well who cares? > [50:40] And the standard answer is oh that there are vulnerable > communities of poor people who depend on them [ coral reefs ] for fish and > nutrients and you know there are numbers of how many hundreds of millions > of people depend on reefs for their livelihood and tourism and all this > kind of stuff. And then there is the other sort of standard answer, oh > this is a necessary component of the homeostatic earth system and if we > lose these that humans are the next domino to fall. I personally don't > believe any of that. I actually think if you sterilize the ocean, yes > vulnerable people would be hurt, poor people would be hurt, but that we'd > still have Chicken McNuggets and TV shows and basically we'd be OK. And so > for me its really this sort of tragedy - and maybe this is a middle class > American viewpoint - but that you've had billions of years of > evolution producing all this biodiversity and because we want to have - you > know economists estimate it would cost something like 2% of GDP to > eliminate carbon dioxide emissions from our energy system, maybe it would > cost a few percent more of GDP so because we want to be a few percent > richer we're willing to lose all this, all these ecosystems, we're willing > to lose the Arctic ecosystem, we're willing to lose these marine ecosystems > and to me its a little bit like somebody saying well I have enough money so > I can run through the Metropolitan Museum and just slash up all the > paintings.... And so for me being a middle class American who is gonna > have TV shows and Chicken McNuggets and burgers and things, for me its more > this kind of ethical kind of thing. Obviously, if you depend on your > livelihood for fishing on a reef you're going to have a different > perspective. But that's enough of that. > > > -- > You received this message because you are subscribed to the Google Groups > "geoengineering" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to [email protected]. > To post to this group, send email to [email protected]. > Visit this group at http://groups.google.com/group/geoengineering?hl=en. > For more options, visit https://groups.google.com/groups/opt_out. > > > -- _______________ Ken Caldeira Carnegie Institution for Science Dept of Global Ecology 260 Panama Street, Stanford, CA 94305 USA +1 650 704 7212 [email protected] http://dge.stanford.edu/labs/caldeiralab @kencaldeira *Caldeira Lab is hiring postdoctoral researchers.* *http://dge.stanford.edu/labs/caldeiralab/Caldeira_employment.html* Check out the profile of me on NPR's All Things Considered<http://www.npr.org/2013/04/22/176344300/this-scientist-aims-high-to-save-the-worlds-coral-reefs> -- You received this message because you are subscribed to the Google Groups "geoengineering" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To post to this group, send email to [email protected]. Visit this group at http://groups.google.com/group/geoengineering?hl=en. For more options, visit https://groups.google.com/groups/opt_out.
