Really feels like you're shooting from the hip Alvia-- I don't think that's a useful approach.
Will "we" do more than 20%? If OIF is effective with acceptable impacts, I think people will do essentially 100% of the area where it makes sense to do so. Methods of distributing without ships will be fairly straightforward to implement. I wouldn't consider weather related constraints on ship-based distribution to be a factor. D On Dec 16, 11:57 am, "Alvia Gaskill" <[email protected]> wrote: > 200MtC is 20% of the available HNLC areas. Do you expect to do more than > this? It is likely that for various reasons, 100% will not be possible, > e.g. weather, therefore some lesser percentage would be more realistic. > > ----- Original Message ----- > From: "Dan Whaley" <[email protected]> > To: "geoengineering" <[email protected]> > Sent: Tuesday, December 16, 2008 1:58 PM > Subject: [geo] Re: Ocean Fertilization, an Incomplete Answer with Uncertain > > Long Term Implications Say Aussies > > I think it is a distraction to bring in the notion of effectiveness as > some % against emissions. The comparison of one technique against > another does not change if one compares it ton for ton or if one > compares it after the application of a common divisor. after > all.... if x = y, then x/z = y/z as well. > > If you can find a larger lever on carbon somewhere else, then it > should be explored, and if appropriate, perhaps it should be pulled > too. we're going to have to pull on all the smaller levers as well. > We have a huge problem, and a lot of resident atmospheric CO2. I > think we all get the point. Having looked hard at this for the last > couple years, I still haven't come across what feels to be another > plausible option to get as large an amount of carbon out of the > atmosphere per year. > > I would like to understand your basis for the 200MtC number. Is this > a back of the napkin analysis, or is this based on modeling work you > have seen? > > One of your arguments seems to be that getting to theoretical numbers > based on assumed "full deployment" represents a large logistical > challenge, and therefore we should use smaller numbers. Clearly > logistics need to be addressed. However, lets make sure we don't > conflate an appraisal of potential with an assessment of > implementation challenges. Lackner's carbon trees have in my opinion > significant logistical challenges (in addition to aesthetic ones) for > deployment-- but I'm willing to engage on a max theoretical potential > vs. cost / ton discussion independently. > > Frankly, I think if our primary challenge lies in trying to optimize > the distribution of iron across a specific % of the ocean basin, we're > probably up to the task. I can think of much harder problems. > > D > > On Dec 16, 8:35 am, "Alvia Gaskill" <[email protected]> wrote: > > My point is that the 25% figure is the most generous assessment that can > > be > > made at present. A more realistic one would assume far less than 100% > > coverage of the HNLC areas and a much higher total GHG emissions. In that > > more likely scenario, OIF provides for 200MtC removal and total emissions > > are 10GtC in which case OIF is responsible for offsetting 4% of > > atmospheric > > gain and 2% of total emissions. To get to 200MtC removal will be an > > enormous task. By 2050, if emissions have doubled, OIF would remove only > > 2% > > of atmospheric gain, a measureable, but minor mitigation technology. > > > ----- Original Message ----- > > From: "Dan Whaley" <[email protected]> > > To: "Alvia Gaskill" <[email protected]> > > Sent: Tuesday, December 16, 2008 10:35 AM > > Subject: Re: Ocean Fertilization, an Incomplete Answer with Uncertain Long > > > Term Implications Say Aussies > > > Alvia, > > > I find this comment very strange: > > > "OIF gets a lot of attention for a technology that will never remove > > more than 25% of CO2 added to the atmosphere." > > > Can you explain your thinking? I assume you are by now tired of > > looking at McKinsey curves and hearing speaker after speaker refer to > > the need to take a portfolio approach, etc. etc. > > > 25% of annual emissions is quite a large number. We should be so > > lucky. This would be larger than any single constituent of the global > > McKinsey cost of abatement curve. Nearly three times worldwide > > deployment of CCS. > > > Oliver, I am quite intrigued by your comments ... Can you refer me to > > the specific paper(s) pls? > > > Dan > > > D > > > On Dec 15, 12:32 pm, "Alvia Gaskill" <[email protected]> wrote: > > > Regarding the "absorption limit" for OIF, what should be the baseline > > > against which the effectiveness of OIF is evaluated? Should it be the > > > total of human CO2 emissions, the total of all human GHG emissions or > > > should it be the amount of CO2 that is added to the atmospheric > > > inventory > > > annually? > > > > If the maximum quantity that can be captured by OIF enhanced plankton is > > > constant, wouldn't the percent effectiveness decrease as human emissions > > > increase as they likely will and also, as the natural sinks become less > > > effective? > > > > I participated in a discussion recently regarding this issue, although > > > not > > > about OIF specifically. The decision was to base the effectiveness on > > > the > > > amount of CO2 added to the air and not the total emissions, assuming > > > that > > > about half the emissions wind up in the air. This also relates to how > > > carbon credits from OIF would be calculated. Do the credits apply to the > > > emissions or to the amount added to the air? > > > > Example calculations to illustrate these points: > > > > 1GtC from OIF/4GtC added to air each year in 2008 = 25% > > > > 1GtC/8GtC emitted by humans in 2008 = 13% > > > > 1GtC/6.66GtC as CO2 emitted by humans in 2008 = 15% > > > > 1GtC/16GtC emitted by humans in 2050 (arbitrary emissions and date, not > > > any specific scenario) = 6% > > > > OIF gets a lot of attention for a technology that will never remove more > > > than 25% of CO2 added to the atmosphere. > > > > ----- Original Message ----- > > > From: Ken Caldeira > > > To: [email protected] > > > Cc: [email protected] > > > Sent: Monday, December 15, 2008 1:00 PM > > > Subject: Re: [geo] Ocean Fertilization, an Incomplete Answer with > > > Uncertain Long Term Implications Say Aussies > > > > And while we are thinking deeply about this potential threat, we will > > > continue to strip mine the ocean of edible fish. > > > > I am not a big fan of ocean fertilization, but I do not think that > > > anybody > > > has come up with any plausible damage from a well-managed ocean > > > fertilization program that is of the same order-of-magnitude as what we > > > are already routinely doing to the ocean with overfishing. > > > > I am even less clear on what the "irreversible risk" is supposed to be > > > from a well-managed ocean fertilization program. Assuming that you > > > monitor > > > for anticipated risks, what could happen that would not be likely to > > > reverse itself after fertilization ceases? > > > > [ By well-managed, I mean that endemic species abundances and oxygen > > > contents and things like that are being monitored, so that you do not > > > induce extinctions ... which are irreversible. ] > > > > [ This is not an excuse to induce more damage, but just a comment to > > > note > > > that attention to various potential risks are often incommensurate with > > > the amount of actual risk incurred. ] > > > > On Mon, Dec 15, 2008 at 5:29 AM, Alvia Gaskill <[email protected]> > > > wrote: > > > >http://www.alertnet.org/thenews/newsdesk/SP39844.htm > > > > RPT-FEATURE-Scientists urge caution in ocean-CO2 capture schemes 15 Dec > > > 2008 13:04:25 GMT > > > Source: Reuters > > > (Repeats story that moved at 0000 GMT) > > > > By David Fogarty, Climate Change Correspondent, Asia > > > > SINGAPORE, Dec 15 (Reuters) - To some entrepreneurs, the wild and icy > > > seas > > > between Australia and Antarctica could become a money spinner by > > > engineering nature to soak up carbon dioxide and then selling carbon > > > credits worth millions of dollars. > > > > To some scientists and many nations, though, the concept of using nature > > > to mop up mankind's excess CO2 to fight global warming is fraught with > > > risk and uncertainty. > > > > An analysis by a leading Australian research body has urged caution and > > > says more research is crucial before commercial ventures are allowed to > > > fertilise oceans on a large scale and over many years to capture CO2. > > > > "I don't think the scientific community has even sat down and made a > > > list > > > of the things we need to check before we feel comfortable that this > > > would > > > be a low-risk endeavour," said one of the Australian report's authors, > > > Tom > > > Trull. > > > > "We never even designed measurement programmes to look at ecological > > > change and the risks," said Trull, Ocean Control of Carbon Dioxide > > > programme leader at the Antarctic Climate and Ecosystems Cooperative > > > Research Centre (ACE CRC) in Hobart. > > > > Scientists say sprinkling the ocean surface with trace amounts of iron > > > or > > > releasing other nutrients over many thousands of square kilometres > > > promotes blooms of tiny phytoplankton, which soak up carbon dioxide in > > > the > > > marine plants. When the phytoplankton die, they drift to the ocean > > > depths, > > > along with the carbon locked inside their cells where it is potentially > > > stored for decades or centuries in sediments on the ocean floor. > > > > Firms eyeing this natural carbon sink hope to commercialise it to yield > > > carbon credits to help industries offset their emissions. > > > > The problem is no one knows exactly how much carbon can be captured and > > > stored in this way, for how long, or the risks to ocean ecosystems from > > > such large-scale geo-engineering. > > > > Some scientists fear such schemes could change species composition in > > > the > > > oceans, increase acidity or cause oxygen depletion in some areas, even > > > promote the release of another powerful greenhouse gas, nitrous oxide. > > > > BLOOMING > > > > "Ocean fertilisation may cause changes in marine ecosystem structure and > > > biodiversity, and may have other undesirable effects," says the ACE CRC > > > position analysis on ocean fertilisation science and policy, soon to be > > > publicly released. > > > > "While controlled iron fertilisation experiments have shown an > > ... > > read more » --~--~---------~--~----~------------~-------~--~----~ You received this message because you are subscribed to the Google Groups "geoengineering" group. 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