Hi Mike, The figure is useful: If 597 (atm) had been in equilibrium with 900 (mixed layer) pre-industrial, how can 597+165 be within a few Gt(C) of equilibrium with 900 + 18? If the atm. and the mixed layer of the sea are that far out of equilibrium, seems to me the sink will operate for a while (decades) even if future emissions = current sink over that period. In other words, what I am questioning is whether there would, within a year, be a hugely reduced gradient. Am I misinterpreting the numbers in the figure???
It will be nice to sort this out!! John John Harte Professor of Ecosystem Sciences ERG/ESPM 310 Barrows Hall University of California Berkeley, CA 94720 USA [email protected] On Jan 25, 2015, at 6:16 PM, Mike MacCracken <[email protected]> wrote: > Hi John—So I have attached a diagram of the carbon cycle from IPCC AR4WG1 > Figure 7.3 that shows natural flows (in black) and then the augmentations as > a result of human activities (in red) > > There is a time constant for uptake of particular molecules of CO2 into the > mixed layer, so mass in mixed layer divided by atmospheric flux, and that is > 10 years (what I think you are referring to). I don’t think, however, that > this is what determines the lag time for the net flux and so what counts in > what we have been talking about—basically, if there were suddenly no > gradient, there would immediately be no net flux and it does not matter which > molecule is where. So, in my view, what matters is the gradient that is > created by each year’s emissions, and as that goes down, the gradient will be > less, and if the atmospheric concentration were suddenly held stable, the > driving gradient would pretty quickly go to zero (there would still be the > gradient with the deep ocean as its cycle time is of order 1000 years, so the > flux to the deep ocean would continue. > > And I don’t think there is anywhere near a 10-year lag in the concentration > gradient between the atmosphere and the concentration at the top of the mixed > layer—nor do I think that the vertical mixing time down of order 100-200 > meters in the upper ocean layer is anything like a decade given wave and > isopychnal mixing and wind driven flows—I’d suggest less than a year, but > that is a guess. [WE NEED AN AUTHORITATIVE COMMENT FROM KEN C]. > > Best, Mike > > > > > On 1/25/15, 6:10 PM, "John Harte" <[email protected]> wrote: > >> Mike, I could be wrong but i was under the impression that the relevant time >> constant (inverse rate const.) characterizing the gradient-driven gross >> flow of CO2 from air to sea is on the order of a decade or two. A result I >> thought obtained from C14 tracer studies. I am also under the impression >> that the year to year variation in the sink strength does not track annual >> emissions very closely, suggesting that there are longer time constants in >> the system (as well as "noise" from variations in wind etc. and inter annual >> variability in the terrestrial sink). >> >> It's been a while since I looked at this so maybe my understanding is out of >> date. >> >> >> Cheers, >> >> John >> >> John Harte >> Professor of Ecosystem Sciences >> ERG/ESPM >> 310 Barrows Hall >> University of California >> Berkeley, CA 94720 USA >> [email protected] >> >> >> >> On Jan 25, 2015, at 1:27 PM, Mike MacCracken <[email protected]> wrote: >> >>> Re: [geo] Energy Planning and Decarbonization Technology | The Energy >>> Collective >>> Hi John and Greg—So responding to both messages (and I pasted John’s into >>> the thread) >>> >>> I would think the terrestrial biosphere time constant is a decade or two, >>> but for the ocean, I’d suggest that it is much shorter. My understanding is >>> that the time constant of the wind-stirred ocean mixed layer is a year or >>> two—not a decade or two. Changing the net flux rate to the deep ocean would >>> be pretty slow, but that net flux is pretty small. >>> >>> And so, how would it work. Well, in terms of the net flux to the ocean, the >>> CO2 is driven into the upper ocean by the gradient between the atmosphere >>> and the upper ocean, so once one stabilizes the atmospheric concentration >>> and the ocean mixed layer concentration catches, up, there will be no >>> gradient to drive the flux. >>> >>> Well, this is not quite correct as the net flux to the deep ocean would >>> continue, so there could be a net flux from the atmosphere to the upper >>> ocean to make up that difference. However, the ocean surface layer would >>> also continue to warm as there is a lag in the thermal term—and so the >>> warmer the mixed layer, the higher the CO2 partial pressure would be and >>> this would tend to resist uptake of CO2. >>> >>> In terms of gross fluxes, the carbon rich upwelling waters would end up >>> giving off a bit more CO2 with CO2 stabilization as opposed to the >>> situation were the CO2 higher, and the uptake in high latitudes where water >>> is cold would not be going up because the atmosphere-upper ocean gradient >>> would be less, so again, one would lose the ocean sink, and that would mean >>> that a greater share of any emissions that did occur (so in reducing the >>> CO2 emissions from 37 Gt CO2/yr, one does not get to assume the ocean sink >>> would continue as it has—and I suspect that would be a pretty fast >>> adjustment. >>> >>> For the biosphere, John suggests that he is quite concerned about the >>> continuance of the terrestrial sink (basically, it seems, whether or not >>> one stabilizes the CO2 concentration). >>> >>> So, as I indicated initially, it seems to me that one would pretty quickly >>> need to be taking up 90% of the 37 GtCO2/yr by your proposed approach—and >>> that is a lot of carbon to be taking up. Hence, I’ll stand by my earlier >>> statement that it will be hard for CDR/atmospheric and oceanic scrubbing to >>> make much of a difference with respect to slowing the rate of climate >>> change until emissions drop a lot. >>> >>> Mike >>> >>> >>> Msg from John Harte—combined into this thread. >>> >>> Mike, I think the truth is flanked by your's and Greg's statements. If we >>> were to reduce emissions starting immediately so that each year from here >>> on out we emit only about half current emissions, then for a decade or two, >>> at least, the current carbon sink would roughly equal emissions and the CO2 >>> level would be roughly constant, as Greg suggests. The concentration >>> gradient between air and sea would slowly shrink however and so in the >>> longer run the sink strength would diminish and emissions would have to be >>> reduced further. At a steady annual flow from air to sea of 15 - 20 >>> Gt(CO2)/y, however, it would take decades before there was an appreciable >>> diminishment of that sink flow. The real shorter-term danger I think is >>> that soil warming and forest dieback leading to terrestrial sources of CO2, >>> along with possible CH4 releases, all because of the warming associated >>> with trying to keep a steady 400 ppm of CO2, would necessitate much greater >>> emissions reduction and the sooner we achieve that the better. >>> >>> John Harte >>> Professor of Ecosystem Sciences >>> ERG/ESPM >>> 310 Barrows Hall >>> University of California >>> Berkeley, CA 94720 USA >>> [email protected] <x-msg://4873/[email protected]> >>> >>> >>> On 1/25/15, 3:23 PM, "Greg Rau" <[email protected] >>> <x-msg://4873/[email protected]> > wrote: >>> >>>> I'm not necessarily advocating lowering air pCO2, but stabilizing pCO2 say >>>> at the present 400 uatms. If this is stable, how does additional ocean >>>> degassing ensue? Exactly how much CDR would be needed to achieve this, the >>>> resulting response of natural CDR and natural emissions, and the required >>>> time course of this I will leave to the modelers. Ditto for achieving >>>> stability via pure anthro emissions reduction. Obviously, some combination >>>> of these will, in my opinion, be needed to stabilize pCO2. Anthro >>>> emissions reduction would appear to have significant technological and >>>> policy awareness lead relative to CDR. I'm suggesting this needs to >>>> change, in case emissions reduction alone continues to fail to achieve its >>>> promise. >>>> >>>> As for reducing air pCO2, this already happens on an intra-annual basis >>>> thanks to natural CDR and in spite of ocean degassing: >>>> https://scripps.ucsd.edu/programs/keelingcurve/2013/10/23/the-annual-rise-in-co2-levels-has-begun/#more-940 >>>> Is it unthinkable that this decline couldn't be increased to some >>>> degree via human intervention? Wouldn't it be desirable/necessary to >>>> investigate this in the now likely event that current policies and actions >>>> have us blowing by the pCO2 "safety threshold" for decades if not >>>> centuries, or beyond if permafrost/clathrate degassing ensues? >>>> Greg >>>> >>>>> >>>>> >>>>> >>>>> >>>>> From: Mike MacCracken <[email protected] >>>>> <x-msg://4873/[email protected]> > >>>>> To: Greg Rau <[email protected] <x-msg://4873/[email protected]> >; >>>>> Geoengineering <[email protected] >>>>> <x-msg://4873/[email protected]> > >>>>> Sent: Sunday, January 25, 2015 11:10 AM >>>>> Subject: Re: [geo] Energy Planning and Decarbonization Technology | The >>>>> Energy Collective >>>>> >>>>> >>>>> >>>>> Re: [geo] Energy Planning and Decarbonization Technology | The Energy >>>>> Collective >>>>> Hi Greg--The problem with your calculation is that if you were to take >>>>> CO2 out of the atmosphere, the ocean and biosphere would readjust to the >>>>> lower atmospheric concentration and return to the atmosphere that they >>>>> have taken up earlier when the original amount of CO2 was emitted. Thus, >>>>> you really have to figure out how to sequester 90+% of the 37 Gt CO2/yr >>>>> that is emitted—you don’t get to keep counting the 20 Gt CO2 taken up by >>>>> the ocean and the biosphere. >>>>> >>>>> Mike >>>>> >>>>> >>>>> On 1/25/15, 1:25 PM, "Greg Rau" <[email protected] >>>>> <x-msg://4873/[email protected]> > wrote: >>>>> >>>>>> Just to be clear, we currently emit 37.0 GT CO2/yr, yet in the short >>>>>> term only 17.5 Gt/yr remain in the atmosphere, the rest being removed by >>>>>> natural CDR (reviewed here: >>>>>> http://www.nature.com/nclimate/journal/v4/n10/full/nclimate2392.html ). >>>>>> So our net emissions is 17.5 Gt/yr. Cutting this by 90% via enhanced >>>>>> CDR alone would mean removing an additional 15.8 GT CO2/yr over and >>>>>> above the 19.5 Gt/yr already removed, a 81% increase in CDR. Is this >>>>>> sufficient to stabilize air pCO2 or lower pCO2? If the latter then we'd >>>>>> also have to contend with legacy CO2 degassing from the ocean. It should >>>>>> be easier to reduce emissions than increase CDR, but then how is that >>>>>> going? I'd say it's time to find out just how easy or hard additional >>>>>> CDR is, relative to the technical, economic and political difficulties >>>>>> of emissions reduction, and relative to the consequences if the latter >>>>>> strategy continues to seriously underperform. >>>>>> Greg >>>>>> >>>>>>> >>>>>>> >>>>>>> >>>>>>> >>>>>>> From: Mike MacCracken <[email protected] >>>>>>> <x-msg://4873/[email protected]> > >>>>>>> To: Greg Rau <[email protected] <x-msg://4873/[email protected]> >>>>>>> >; Geoengineering <[email protected] >>>>>>> <x-msg://4873/[email protected]> > >>>>>>> Sent: Sunday, January 25, 2015 8:27 AM >>>>>>> Subject: Re: [geo] Energy Planning and Decarbonization Technology | >>>>>>> The Energy Collective >>>>>>> >>>>>>> >>>>>>> >>>>>> Re: [geo] Energy Planning and Decarbonization Technology | The Energy >>>>>> Collective >>>>>> Let me expand my quick description to be 90% cut in human-induced >>>>>> emissions (on top of all the natural sinks), so natural CDR does not >>>>>> count. >>>>>> >>>>>> And on the proposed removal industry, for $100 per ton of CO2, an awful >>>>>> lot could be done to replace fossil fuels with other sources of energy, >>>>>> or even better efficiency, a huge amount of which could be done for much >>>>>> less, if we’d try. So, nice that there is a CO2 removal approach as a >>>>>> backstop to what the cost of changing energy would be—basically, you are >>>>>> suggesting it should cost less than $100 per ton of CO2 to address the >>>>>> problem. With the new paper in Nature (lead author is a former intern >>>>>> that worked with me at the Climate Institute) that the social cost of >>>>>> CO2 is more than twice the cost of, then it makes huge economic sense to >>>>>> be addressing the problem. So, indeed, let’s get on with it—research >>>>>> plus actually dealing with the issue. >>>>>> >>>>>> Mike >>>>>> >>>>>> >>>>>> >>>>>> >>>>>> On 1/24/15, 1:40 PM, "Greg Rau" <[email protected] >>>>>> <x-msg://4873/[email protected]> > wrote: >>>>>> >>>>>>> Mike, >>>>>>> If it takes "a 90% cut in CO2 to stop the rise in atmospheric >>>>>>> concentration", we are already more than half way there thanks to >>>>>>> natural CDR. About 55% of our CO2 emissions are mercifully removed from >>>>>>> air via biotic and abiotic processes. So just 35% to go? >>>>>>> As for "CDR replacing the fossil fuel industry", here's one way to do >>>>>>> that: http://www.pnas.org/content/110/25/10095.full , but low fossil >>>>>>> energy prices (or lack of sufficient C emissions surcharge) are >>>>>>> unlikely to make this happen. Certainly agree that we need all hands >>>>>>> and ideas on deck in order to stabilize air CO2. But for reasons that >>>>>>> continue to baffle me, that is not happening at the policy, decision >>>>>>> making, and R&D levels it needs to. >>>>>>> Greg >>>>>>> >>>>>>>> >>>>>>>> >>>>>>>> >>>>>>>> >>>>>>>> From: Mike MacCracken <[email protected] >>>>>>>> <x-msg://4873/[email protected]> > >>>>>>>> To: Geoengineering <[email protected] >>>>>>>> <x-msg://4873/[email protected]> > >>>>>>>> Sent: Saturday, January 24, 2015 9:06 AM >>>>>>>> Subject: Re: [geo] Energy Planning and Decarbonization Technology | >>>>>>>> The Energy Collective >>>>>>>> >>>>>>>> >>>>>>>> >>>>>>>> Re: [geo] Energy Planning and Decarbonization Technology | The Energy >>>>>>>> Collective >>>>>>>> In terms of an overall strategy, it takes of order a 90% cut in CO2 >>>>>>>> emissions to stop the rise in the atmospheric concentration, and that >>>>>>>> has to happen to ultimately stabilize the climate (and it would be >>>>>>>> better to have the CO2 concentration headed down so we don’t get to >>>>>>>> the equilibrium warming for the peak concentration we reach (recalling >>>>>>>> we will be losing sulfate cooling). >>>>>>>> >>>>>>>> Thus, to really stop the warming, CDR in its many forms has to be at >>>>>>>> least as large as 90% of CO2 emissions (from fossil fuels and >>>>>>>> biospheric losses). That is a lot of carbon to be taking out of the >>>>>>>> system by putting olivine into the ocean, biochar, etc. at current >>>>>>>> global emissions levels (that are still growing). The greater the >>>>>>>> mitigation (reduction in fossil fuel emissions), the more effective >>>>>>>> CDR can be—what would really be nice is CDR replacing the fossil fuel >>>>>>>> industry so ultimately it is as large. I’d suggest this is why it is >>>>>>>> really important to always be mentioning the importance of all the >>>>>>>> other ways, in addition to CDR, to be cutting emissions—that is really >>>>>>>> critical. >>>>>>>> >>>>>>>> Mike >>>>>>>> >>>>>>>> >>>>>>>> On 1/24/15, 10:19 AM, "Stephen Salter" <[email protected] >>>>>>>> <x-msg://4873/[email protected]> > wrote: >>>>>>>> > > Hi All > > Paragraph 2 mentions 'carbon negative' nuclear energy. The carbon emissions > from a complete, working nuclear power station are mainly people driving to > work. But digging, crushing and processing uranium ore needs energy and > releases carbon in inverse proportion to the ore grade. There were some > amazingly high grade ores, some once even at the critical point for reaction, > but these have been used. Analysis by van Leeuwen concludes that the carbon > advantage of present nuclear technology over gas is about three but that the > break-even point comes when the ore grade drops to around 100 ppm. This > could happen within the life of plant planned now. > > As we do not know how to do waste disposal we cannot estimate its carbon > emissions. But just because we cannot calculate them does not mean that they > are zero. > > Stephen > > > > Emeritus Professor of Engineering Design. School of Engineering. University > of Edinburgh. Mayfield Road. Edinburgh EH9 3JL. Scotland [email protected] > <x-msg://4873/[email protected]> Tel +44 (0)131 650 5704 Cell 07795 203 195 > WWW.see.ed.ac.uk/~shs <http://WWW.see.ed.ac.uk/~shs> > <http://WWW.see.ed.ac.uk/~shs> YouTube Jamie Taylor Power for Change > > On 24/01/2015 14:56, Andrew Lockley wrote: > > > > > Poster's note : none of this explains why there's any need for integration. > Chucking olivine in the sea seems easier and cheaper than all. > > > http://theenergycollective.com/noahdeich/2183871/3-ways-carbon-removal-can-help-unlock-promise-all-above-energy-strategy > > > 3 Ways Carbon Removal can Help Unlock the Promise of an All-of-the-Above > Energy Strategy > > > January 24, 2015 > > > > “We can’t have an energy strategy for the last century that traps us in the > past. We need an energy strategy for the future – an all-of-the-above > strategy for the 21st century that develops every source of American-made > energy.”– President Barack Obama, March 15, 2012 > > > An all-of-the-above energy strategy holds great potential to make our energy > system more secure, inexpensive, and environmentally-friendly. Today’s > approach to all-of-the-above, however, is missing a key piece: carbon dioxide > removal (“CDR”). Here’s three reasons why CDR is critical for the success of > an all-of-the-above energy strategy: > > > 1. CDR helps unite renewable energy and fossil fuel proponents to advance > carbon capture and storage (“CCS”) projects. Many renewable energy advocates > view CCS as an expensive excuse to enable business-as-usual fossil fuel > emissions. But biomass energy with CCS (bio-CCS) projects are essentially > “renewable CCS” (previously viewed as an oxymoron), and could be critical for > drawing down atmospheric carbon levels in the future. As a result, fossil CCS > projects could provide a pathway to “renewable CCS” projects in the future. > Because of the similarities in the carbon capture technology for fossil and > bioenergy power plants, installing capture technology on fossil power plants > today could help reduce technology and regulatory risk for bio-CCS projects > in the future. What’s more, bio-CCS projects can share the infrastructure for > transporting and storing CO2 with fossil CCS installations. Creating such a > pathway to bio-CCS should be feasible through regulations that increase > carbon prices and/or biomass co-firing mandates slowly over time, and could > help unite renewable energy and CCS proponents to develop policies that > enable the development of cost-effective CCS technology. > > > 2. CDR bolsters the environmental case for nuclear power by enabling it to be > carbon “negative”: Many environmental advocates say that low-carbon benefits > of nuclear power are outweighed by the other environmental and safety > concerns of nuclear projects. The development of advanced nuclear projects > paired with direct air capture (“DAC”) devices, however, could tip the scales > in nuclear’s favor. DAC systems that utilize the heat produced from nuclear > power plants can benefit from this “free” source of energy to potentially > sequester CO2 directly from the atmosphere cost-effectively. The ability for > nuclear + DAC to provide competitively-priced, carbon-negative energy could > help convince nuclear power’s skeptics to support further investigation into > developing safe and environmentally-friendly advanced nuclear systems. > > > 3. CDR helps enable a cost-effective transition to a decarbonized economy: > Today, environmental advocates claim that prolonged use of fossil fuels is > mutually exclusive with preventing climate change, and fossil fuel advocates > bash renewables as not ready for “prime time” — i.e. unable to deliver the > economic/development benefits of inexpensive fossil energy. To resolve this > logjam, indirect methods of decarbonization — such as a portfolio of low-cost > CDR solutions — could enable fossil companies both to meet steep emission > reduction targets and provide low-cost fossil energy until direct > decarbonization through renewable energy systems become more cost-competitive > (especially in difficult to decarbonize areas such as long-haul trucking and > aviation). > > > Of course, discussion about the potential for CDR to enable an > all-of-the-above energy strategy is moot unless we invest in developing a > portfolio of CDR approaches. But if we do make this investment in CDR, an > all-of-the-above energy strategy that delivers a diversified, low-cost, and > low-carbon energy system stands a greater chance of becoming a reality. > > > Noah Deich > > > Noah Deich is a professional in the carbon removal field with six years of > clean energy and sustainability consulting experience. Noah currently works > part-time as a consultant for the Virgin Earth Challenge, is pursuing his MBA > from the Haas School of Business at UC Berkeley, and writes a blog dedicated > to carbon removal (carbonremoval.wordpress.com > <http://carbonremoval.wordpress.com> <http://carbonremoval.wordpress.com > <http://carbonremoval.wordpress.com/> <http://carbonremoval.wordpress.com/> > <http://carbonremoval.wordpress.com/> <http://carbonremoval.wordpress.com/> > > ) > > > -- > 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] > <x-msg://4873/[email protected]> . > To post to this group, send email to [email protected] > <x-msg://4873/[email protected]> . > Visit this group at http://groups.google.com/group/geoengineering. > For more options, visit https://groups.google.com/d/optout. > > > >>>>> >>>>> >>>>> >>>>> >>>>> >>>> >>>> > <Anthropogenic_carbon_cycle.png> -- You received this message because you are subscribed to the Google Groups "geoengineering" group. 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