Caldeira et al showed that moving water in this way causes warming. A
On 8 Sep 2017 00:15, "'Robert Tulip' via geoengineering" < [email protected]> wrote: > Thanks Cristoph. > Deep Ocean Water, with volume about a billion cubic kilometres below the > thermocline, has about three ppm nitrate and phosphate, about 3000 cubic > kilometres of each, as I understand the numbers. Tidal pumping arrays along > the world's continental shelves could raise enough DOW to the surface, > mimicking natural algae blooms, to fuel controlled algae production at the > scale required for seven million square kilometres of factories. Piping > CO2 from power plants etc out to ocean algae farms could clean up all the > polluted air of the world. > Robert Tulip > > > ------------------------------ > *From:* Christoph Voelker <[email protected]> > *To:* [email protected] > *Sent:* Friday, 8 September 2017, 8:43 > *Subject:* Re: [geo] Carbon budget/removal in NYTimes interactive > > I must admit that I am getting skeptical when I hear numbers in that order > of magnitude: > The total net primary production in the oceans presently is about 50 Gt > carbon, and 80% of that is converted back into inorganic carbon (and > nutrients) by heterotrophs before it gets a chance to sink out from the > sunlit upper layer of the ocean. The roughly 10 Gt carbon (some newer works > even estimate just 6 Gt carbon) that sink out have to be balanced by the > upward mixing of nutrients (and a little bit by atmospheric deposition of > bioavailable nitrogen and phosphorus) in the Redfield ratio of about > 106:16:1 of C:N:P. > So, if you want to remove 20 Gt carbon per year from the atmosphere, you'd > have to increase the nutrient supply to the total surface ocean by a factor > of three, maybe four. Maybe I am a bit too pessimistic here, because there > are species like Sargassum which have a higher C:N:P ratio than the average > phytoplankton, so you get somewhat more carbon per nitrogen/phosphorus. But > even if it is just doubling, I can't imagine that you can sustain such a > nutrient consumption by fertilizing from outside the ocean (especially > since phosphorus is scarce already now), you'd have to tap into the > inorganic nutrients stored in the deep ocean. How long can you do that? > If we assume that we harvest all the 20 Gt carbon in algae from these > factories and do something durable with them (to minimize lossed through > heterotrophy and problems with creating oxygen minimum zones), we > effectively remove nitrogen/phosphorus from the ocean. How much is that per > year? > Let us for simplicity assume Redfield ratios, I grant errors by a factor > of two or so. 20 Gt carbon then corresponds to (20 > g/12(g/mol)/6.625(molC/molN))*1.0e15 or about 2.5e14 mol nitrogen. The > ocean has a volume of 1.33e18 m^3, and the average concentration of > available nitrogen (mostly nitrate) is 30 micromol/L or mmol/m^3 > (calculated from the world ocean atlas), most of that is in the deep ocean. > This gives a total inventory of 4.0e16 mol nitrogen. 2.5e14 mol/year is > thus more than half of a percent of the total available nitrogen in the > world oceans, which means you could try that for about 150 years, then > everything is gone At that pace, nitrogen fixers are unlikely to resupply > the loss (nowaday, the residence time of nitrogen is roughly 5000 years), > and they can do that only for nitrogen, not for phosphorus anyway. Letting > technological problems aside (like: How do you move 2.5% of the total > nitrogen in the world oceans evry year up to an area 2% of the ocean > surface) I would call the whole idea - at least that the scale suggested - > a prime example of an unsustainable process. > Best regards, > Christoph Voelker > > On 07.09.17 23:37, 'Robert Tulip' via geoengineering wrote: > > The assumption behind the NYT interactive model > <https://www.nytimes.com/interactive/2017/08/29/opinion/climate-change-carbon-budget.html?action=click&pgtype=Homepage&clickSource=story-heading&module=opinion-c-col-right-region®ion=opinion-c-col-right-region&WT.nav=opinion-c-col-right-region> > that the upper bound for carbon removal is 12 GT CO2 by 2080 is too slow > and small. We should think five times as much and five times as fast. > Immediate aggressive investment to build industrial algae factories at sea > could remove twenty gigatons of carbon (50 GT CO2) from the air per year by > 2030, using 2% of the ocean surface, funded by use of the produced algae. > That would stabilise the climate and enable no change in emission > trajectories, a policy result that would satisfy both the needs of the > climate and the traditional economy. > Robert Tulip > > > ------------------------------ > *From:* Eric Durbrow <[email protected]> <[email protected]> > *To:* geoengineering <[email protected]> > <[email protected]> > *Sent:* Thursday, 7 September 2017, 3:13 > *Subject:* [geo] Carbon budget/removal in NYTimes interactive > > > FYI There is a slick interactive graphic at the NYTimes that lets people > see if they can meet the world’s carbon budget restriction but a > combination of reduced emissions AND achieving Carbon Removal. > > At > > https://www.nytimes.com/interactive/2017/08/29/ > opinion/climate-change-carbon-budget.html?action=click& > pgtype=Homepage&clickSource=story-heading&module=opinion- > c-col-right-region®ion=opinion-c-col-right-region&WT. > nav=opinion-c-col-right-region > > I failed after clicking on Reduce in all geographic areas and Achieve in > Carbon Removal. > > > > > -- > 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 https://groups.google.com/group/geoengineering. > For more options, visit https://groups.google.com/d/optout. > > > -- > 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 https://groups.google.com/group/geoengineering. > For more options, visit https://groups.google.com/d/optout. > > -- > Christoph Voelker > Alfred Wegener Institute for Polar and Marine Research > Am Handelshafen 12 > 27570 Bremerhaven, Germany > e: [email protected] > t: +49 471 4831 1848 <+49%20471%2048311848> > > -- > 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 https://groups.google.com/group/geoengineering. > For more options, visit https://groups.google.com/d/optout. > > > -- > 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 https://groups.google.com/group/geoengineering. > For more options, visit https://groups.google.com/d/optout. > -- You received this message because you are subscribed to the Google Groups "geoengineering" group. 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