Mike, John, Greg,…There must be many runs of GCMs where the input is an emissions trajectory that simply drops to zero (gradually or suddenly). Yet, my perception is that the experts are unsure of what will ensue in the oceans over the following few decades. (Assumptions are needed about the land sink.) Might this group be able to pool insights and say something definitive?
Rob From: geoengineering@googlegroups.com [mailto:geoengineering@googlegroups.com] On Behalf Of Mike MacCracken Sent: Tuesday, June 16, 2015 4:34 PM To: johnnissen2...@gmail.com; John Harte Cc: Greg Rau; R.D. (Olaf)Schuiling; Geoengineering; CARTER; Oliver Tickell Subject: Re: [geo] World Bank report highlights necessity of (BE)CCS John H and Greg—Sorry, I’m running a bit behind. I want to go back to this issue of how long the carbon sink in the ocean will continue at the magnitude it is. Someone will have a good model to actually run and see, but I’m concerned that the rate will not continue so large for so long. So, the atmosphere works to be in equilibrium with the upper ocean concentration, and that time constant is pretty fast (years to a decade or so). Right now, water at low latitudes comes up supersaturated and emits CO2 to the atmosphere as it warms, so a lower CO2 concentration in the atmosphere will lead to increased emissions. And then as the ocean moves poleward and cools CO2 is taken up and a lower CO2 concentration in atmosphere will mean less is taken up. Now, the upper ocean is also seeking to reach equilibrium with the deep ocean, and this will indeed take a long time given deep ocean circulation time is of order 1000 years. So, the upward flux from deep ocean will continue as is (assuming that the overturning does not change), but would not the downward flux to the deep ocean be decreasing per discussion above? So, it seems to me, the downward circulation aspect of the carbon cycle becomes goes down as the atmospheric concentration stops going up. Thus, I just don’t think it is right that one can assume the net removal rate from the atmosphere to the ocean will persist at its current rate for well into the future as global emissions go down (or go to zero). In the past, the net transfer rate to the deep ocean has gone up as the atmospheric concentration has gone up—why would it not go down as the rate of increase in the CO2 goes to zero? Mike On 6/10/15, 4:54 PM, "John Nissen" <johnnissen2...@gmail.com> wrote: Hi John, Even IPCC admits that there will be dangerous climate change without negative emissions, by which they mean geoengineering of the CO2 removal type (CDR). RCP2.6, the only scenario which has a reasonable chance of keeping global warming below 2 degrees C, relies on negative emissions. So I argue that it is indefensible not to consider what CDR techniques can be implemented. Such consideration will lend force to the efforts to reduce emissions, because people will realise how serious the situation has become. Thus the consideration of geoengineering will be strategically productive, rather than counterproductive as you suggest. We have to find a way to remove CO2 faster than it is being put into the atmosphere. That is the bottom line. BTW, we also have to find a way to cool the Arctic and save the sea ice: that is even more urgent. (CO2 reductions will not help here; nor will CDR.) This will almost certainly require SRM-type geoengineering together will local interventions such as snow generation and ice thickening to restore albedo. Cheers, John On Wed, Jun 10, 2015 at 7:50 PM, John Harte <jha...@berkeley.edu> wrote: I am no more confident than you, Greg, that we will reduce emissions by ~2%/y. That we could do so does not mean we will. My point was simply to address the argument of some who suggest that that no matter how fast we reduce emissions, the CO2 level in the atmosphere will continue to rise and we are doomed to see large and very risky future climate warming. I believe it is both scientifically indefensible and strategically counterproductive to base the case for further research on geoengineering on the grounds that nothing else we can possible do will stave off catastrophe. John Harte Professor of Ecosystem Sciences ERG/ESPM 310 Barrows Hall University of California Berkeley, CA 94720 USA jha...@berkeley.edu On Jun 9, 2015, at 9:05 PM, Greg Rau <gh...@sbcglobal.net> wrote: > I'd say that we are nowhere near reducing global emissions by 2-3% per year > let alone getting to zero emissions. This would seem to up the chances that > we are going to blow through a critical CO2 level which could last more than > 85 years, depending. E.g., if the 2 degree threshold is real and only > requires 1000 Gt more of CO2 emissions to achieve, miraculously stabilizing > anthro emissions at current levels, 37 Gt CO2/yr, gets us to the next 1Tt of > CO2 emitted in under 30 years. Those trying to conserve glacial and sea ice > and permafrost might say we've already passed a point of no return. > > So I side with caution and John N. At our current pace of year-to-year global > CO2 emissions reductions (nonexistent) and with clear AGW and OA, it is time > to seriously ask what are all of our options for managing CO2 and its > consequences. As pointed out in this thread, natural CO2 sinks are already > saving our bacon to the tune by some 18 Gt CO2/yr removed from air. Is it > unthinkable that we cannot increase this uptake by enhancing existing sinks > or inventing new ones that can compete on a cost and efficiency basis with > other methods of CO2 management? In this regard, making supercritical CO2 > from dilute sources and storing it underground (BECCS) is a nonstarter from a > thermodynamics standpoint, not to mention land use impacts of biomass > production plus safety and security issues of underground molecular CO2 > storage. Do we really want the CCS lobby and marketing machine to monopolize > the CDR space, as they have point-source CO2 mitigation, at the expense > of a much broader search for safer and more cost effective CO2 managment > strategies, thus holding hostage any significant movement in mitigating pre- > or post-emissions fossil fuel CO2? And, given what is at stake, can we really > afford to limit ourselves to using less than 30% of the planet in solving a > global problem, i.e., ignore the ocean? I therefore find IPCC's NAS's and > now the World Bank's promotion of aforestation and BECCS as the poster > children of CDR dangerously narrow minded. > > Greg > > -------------------------------------------- > On Tue, 6/9/15, John Harte <jha...@berkeley.edu> wrote: > > Subject: Re: [geo] World Bank report highlights necessity of (BE)CCS > To: "John Nissen" <johnnissen2...@gmail.com> > Cc: "Schuiling, R.D. (Olaf)" <r.d.schuil...@uu.nl>, "gh...@sbcglobal.net" > <gh...@sbcglobal.net>, "geoengineering@googlegroups.com" > <geoengineering@googlegroups.com>, "Peter R Carter" <petercarte...@shaw.ca>, > "Oliver Tickell" <oliver.tick...@kyoto2.org> > Date: Tuesday, June 9, 2015, 3:38 PM > > John, rather > than forgetting that, it is exactly the point I am making. > But it's not half of the actual emitted carbon that goes > down the sink; it is a quantity of carbon equal to half the > emitted carbon. So if we emit no carbon next year, at the > end of the year there will be 4 or 5 Gt less carbon in the > atmosphere. Modeling this out 85 years with a simple > gradient-driven (and thus diminishing) sink rate suggests > that by end of century there could be substantially reduced > atmospheric CO2…even in a scenario in which emissions are > reduced by ~ 2 or 3% per year. > > John HarteProfessor of Ecosystem > SciencesERG/ESPM310 Barrows > HallUniversity of CaliforniaBerkeley, > CA 94720 usajha...@berkeley.edu > > > > > > On Jun 9, 2015, at 3:25 > PM, John Nissen <johnnissen2...@gmail.com> > wrote: > Hi John, > > I think you may be > forgetting that about half the CO2 emitted is immediately > absorbed by land and oceans. The other half has a long > lifetime, measured in centuries (and a fraction of that > measured in millennia). Thus reducing emissions to zero > would only produce a gradual reduction in the atmospheric > CO2 level. Therefore active CO2 removal (CDR) is essential > for quickly reducing that level to a safe value: somewhere > in mid 300s of ppm. > > Cheers, John (just back from holiday and > a conference on ocean acidification) > > > On Wed, Jun 3, 2015 at 1:00 > AM, John Harte <jha...@berkeley.edu> > wrote: > Recall that the natural sink > strength today is about 4 or 5 Gt(C)/y … there is no > reason to think that this sink strength, which is > effectively driven by the difference between the current > atmospheric concentration and the concentration in an > atmosphere in equilibrium with the current ocean > concentration, and which sink has been increasing since > 1990, would rapidly quench until the atmospheric > concentration is well down into the mid 300's ppm > range. > Hence if we reduce > emissions down to a level of roughly 4 or 5 Gt(C)/y we will > see the atmospheric level roughly stabilize and if reduce > emissions to zero, we will see the atmospheric level drop > at a very beneficial pace. > > What would invalidate this > projection is crossing a tipping point in which warming > results in a sharp increase in background C or CH4 emissions > (effectively a negative sink) but the paleo record does not > suggest that such tipping points are lurking at current or > even slightly higher temperatures. > If we do not reduce emissions, there > is a of course a better chance that we will cross such > tipping points in the coming century. > > John HarteProfessor of Ecosystem > SciencesERG/ESPM310 Barrows > HallUniversity of CaliforniaBerkeley, > CA 94720 usajha...@berkeley.edu > > > > > > On May 31, 2015, at 8:39 PM, John > Nissen <johnnissen2...@gmail.com> > wrote: > IPCC and the World bank ignore that we need ramp > up removal technologies until we are removing more CO2 than > we are putting into the atmosphere. This ramp up needs to > start straight away, if we are to have a reasonable chance > of avoiding both dangerous global warming and dangerous > ocean acidification. CCS reduces emissions of CO2 into the > atmosphere, but does not actually remove CO2 as needed to > get the level safely below 350 ppm or so. > There should be a formal complaint > to IPCC about this, as for some other issues. > Cheers, John > On Tue, May 26, 2015 at > 8:53 AM, Schuiling, R.D. (Olaf) <r.d.schuil...@uu.nl> > wrote: > A serious > lack of knowledge about natural processes. A million times > more CO2 has been stored by nature in carbonate rocks than > is present in the oceans, atmosphere and biosphere combined, > and not a word about it, Olaf Schuiling > > > > -----Original Message----- > > From: geoengineering@googlegroups.com > [mailto:geoengineering@googlegroups.com] > On Behalf Of Greg Rau > > Sent: maandag 25 mei 2015 21:55 > > To: geoengineering@googlegroups.com > > Subject: [geo] World Bank report highlights necessity of > (BE)CCS > > > > http://bellona.org/news/climate-change/2015-05-world-bank-report-highlights-necessity-ccs > > > > “We need Bio-CCS to attain carbon neutrality by 2100” > > > > "This statement forms a key area of scientific > consensus, shared by the IPCC in the 5AR and acknowledged by > the World Bank’s report. Achieving the 2°C target will > necessitate negative emissions in the second part of this > century. This can be achieved through the combination of > sustainable bioenergy with CCS. Find out how it works > here." > > > > GR - So says CCS promoters, completely ignoring numerous > other C-negative technologies. > > > > "Importantly, the report warns that beyond 2030, the > scenarios in which CCS is not available or not deployed at > scale, the negative emissions required to keep temperature > change below 2°C or even 3°C have to be generated from the > agriculture, forestry, and other land-use sectors, creating > immense challenges in land-use management." > > > > GR - Completely ignores ocean-based C-negative > technologies. Who says that C-negative methods must be > limited to <30% of the Earth's surface, much of which > is already critical for other uses/services? > > > > "With regards to decarbonisation of the electricity > sector, the report argues that the share of low-carbon or > negative-carbon energy must rise from less than 20% in 2010 > to about 60% in 2050. This is an increase of more than 300% > over 40 years." > > > > GR- There is no way this is going to happen if we limit > ourselves to making concentrated CO2 from flue gas and > storing it in the ground - (BE)CCS. We need to expand > RD&D, marketing and policy way beyond CCS. But how will > this happen as long as well funded, vested interests > continue to sell CCS as the only viable technology? > > > > "The report argues that oil and gas companies can in a > similar fashion reinvent themselves if they develop CCS > technology. A Bellona study has in fact found that the jobs > and skills of today’s North Sea petroleum industry could > largely be preserved when transformed into a CO2 storage > industry." > > > > GR - At last, the real reason to promote CCS, whether or not > it makes technical or economic sense and can compete with > other technologies. The habitability of the planet held > hostage by petroleum industry jobs. Sound familiar? > > > > -- > > 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 geoengineering+unsubscr...@googlegroups.com > <mailto:geoengineering%2bunsubscr...@googlegroups.com> . > > To post to this group, send email to geoengineering@googlegroups.com. > > Visit this group at http://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 geoengineering+unsubscr...@googlegroups.com > <mailto:geoengineering%2bunsubscr...@googlegroups.com> . > > To post to this group, send email to geoengineering@googlegroups.com. > > Visit this group at http://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 geoengineering+unsubscr...@googlegroups.com > <mailto:geoengineering%2bunsubscr...@googlegroups.com> . > > To post to this group, send email to geoengineering@googlegroups.com. > > Visit this group at http://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 geoengineering+unsubscr...@googlegroups.com > <mailto:geoengineering%2bunsubscr...@googlegroups.com> . > To post to this group, send email to geoengineering@googlegroups.com. > Visit this group at http://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 geoengineering+unsubscr...@googlegroups.com<mailto:geoengineering+unsubscr...@googlegroups.com>. To post to this group, send email to geoengineering@googlegroups.com<mailto:geoengineering@googlegroups.com>. Visit this group at http://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 geoengineering+unsubscr...@googlegroups.com. To post to this group, send email to geoengineering@googlegroups.com. Visit this group at http://groups.google.com/group/geoengineering. For more options, visit https://groups.google.com/d/optout.
