Hi Ken, I hope I am not too late to bring this up.
There are two fundamental memes about geoengineering which worry me because the leading scientific evidence suggests they are false: 1. That you can reduce CO2 to a safe level in the atmosphere (as regards its global warming and ocean acidification effects) without CDR geoengineering. 2. That you can prevent catastrophic meltdown of the Arctic ice cap without SRM geoengineering to cool the Arctic. The first meme is widely promoted in the media, who have the mistaken assumption that the CO2 level will drop quickly if you stop emissions, ignoring that the lifetime of CO2 is over a hundred years (and a proportion over 10k years). One often sees statements that a strategy of drastic emissions reduction will reduce the effects of global warming to the extent that adaptation to the worst effects of climate change will be affordable. This strategy is encapsulated by IPCC AR5 in a carbon budget for keeping below 2 degrees C; however this budget is almost certainly bust already because of underestimations of climate sensitivity, warming from methane over 20 years, and albedo loss in the Arctic. Dangers from continued ocean acidification over decades are ignored in AR5. The second meme is promoted by IPCC, Met Office and others, who base their projections of sea ice longevity on models rather than observations. There is an assumption that natural negative feedback will mysteriously appear to offset the forcing from albedo loss, which (between 1979 and 2008) amounted to 0.45 W/m2 averaged globally according to Mark Flanner [1]. The scientists claim that the observed exponential trend of PIOMAS sea ice volume decline [2] cannot and will not continue, hence the summer sea ice will last for many decades. The media seem to believe that emissions reductions can halt Arctic warming and save the sea ice. Even if these two memes cannot be *proved* to be false, the evidence that they might be false is *plausible*, so, on the *precautionary* principle, we should be immediately *preparing* for geoengineering deployment on the necessary scale, whilst seeking more evidence one way or the other. Cheers, John [1] http://www.nature.com/ngeo/journal/v4/n3/abs/ngeo1062.html [2] http://robertscribbler.wordpress.com/tag/sea-ice-melt-by-2016/ On Mon, Aug 11, 2014 at 4:18 PM, Nathan Currier <[email protected]> wrote: > Oh! Could you point me towards those discussions, papers, etc, describing > the mechanism of this? > The volcanic H2O paper I just attached discusses lower stratospheric > warming's role in it, but if true, > what you mention would seem very likely to be involved.....and provide > an example of the kind of thing > I was wondering about.....Nathan > > On Monday, August 11, 2014 3:24:47 AM UTC-4, andrewjlockley wrote: > >> There's an intrinsic connection as SRM warms the tropopause >> >> A >> On 11 Aug 2014 04:24, "Nathan Currier" <[email protected]> wrote: >> >>> Hi, Andrew - I fully agree, and really enjoyed your post "SRM >>> interaction with atmospheric anomalies (plus water)" >>> of several days ago, which had mentioned the importance of "folding >>> events." >>> >>> In this case, I was particularly trying to bring up whether there might >>> be evidence sitting right in front of us coming from >>> Pinatubo itself, but perhaps somewhat obscured from our thoughts by the >>> "questionable meme" of Pinatubo as a primary >>> demonstration of "cooling the planet", that stratospheric SRM might >>> inherently contain forcings of opposing signs - such >>> that its radiative effects would always be the net effects of both >>> negative and positive forcings from its various dynamics. >>> Folding events could potentially get messy with geoE, but I don't think >>> one could say there's any intrinsic connection >>> (at least I haven't heard of one). >>> >>> If it were true that both + and - forcings are always there with this >>> kind of SRM, it might of course still work, but this should lower our >>> confidence >>> level in the concept's ultimate viability considerably, because as I >>> say, you'd really have to keep track of all slight but longer-term positive >>> radiative >>> signals it is putting into the climate system (i.e., cooling the >>> stratosphere, warming us), since you certainly need some degree of >>> prolongation for the technique >>> to have much value......and of course, these are just the kinds of >>> things where we currently seem to know quite little......... >>> >>> Cheers, >>> >>> Nathan >>> >>> >>> >>> >>> On Sunday, August 10, 2014 5:17:04 AM UTC-4, andrewjlockley wrote: >>>> >>>> Great point, Nathan. However, you're ignoring an additional issue. >>>> Warming of the tropopause means it's easier for water to convect or fold in >>>> to the stratosphere. This is a potentially serious problem, and one I put >>>> on the list of unknowns already. >>>> >>>> Bulk air movements also bring more methane into the stratosphere, which >>>> ultimately end up as water. >>>> >>>> My view is that we need urgent improvements in our ability to monitor >>>> and model the tropopause, if we are to have a hope of making SRM >>>> predictable and safe. >>>> >>>> A >>>> On 10 Aug 2014 04:39, "Nathan Currier" <[email protected]> wrote: >>>> >>>>> One very widespread geoengineering 'meme' concerns stratospheric SRM >>>>> and Pinatubo. One reads about it continuously - "like Pinatubo," we will >>>>> “cool the planet” through stratospheric aerosols. How real is this? >>>>> Pinatubo clearly cooled the planet *initially*, but are we sure – really >>>>> sure – that it cooled the planet at all temporal scales? When you >>>>> turn on a conventional coal plant, it, too, “cools the planet”, if you >>>>> care >>>>> to look only at the initial response. >>>>> >>>>> There is no discussion, as far as I remember, on the causes of the >>>>> increased stratospheric water vapor changes in Solomon et al 2010 that I >>>>> brought up recently at this group, a paper suggesting considerable climate >>>>> warming from increased stratospheric H2O. In the attached paper, there’s >>>>> discussion of how volcanic eruptions might impact stratospheric water >>>>> vapor, causing a pulse of increased water vapor over 5-10 years. Although >>>>> the volcano injects water vapor itself, its initial impact is actually to >>>>> *dry* the stratosphere, since the SO2 reaction uses up so much water >>>>> vapor, meaning that the much longer pulsed increase must come from >>>>> perturbations in the stratospheric chemistry/climate itself. One question >>>>> I >>>>> wonder about is how intrinsically tied to the sulfur itself these H2O >>>>> pulses might be, perhaps because of changes in methane oxidation, of the >>>>> kind I was hypothesizing before? In the paper, the modeled increased >>>>> forcing of roughly +.1w/m2 might seem modest, compared to the >>>>> initial large negative forcing of –3w/m2 or so, but one lasts a year, the >>>>> other possibly a decade, and how accurate are these modeled estimates? It >>>>> is clearly far easier to recognize the sudden cooling from the eruption >>>>> when it takes place, than a slight warming signal persisting through a >>>>> much >>>>> longer period of time in an already warming climate system. Yet clearly >>>>> this is vital to understand if anyone is going to be doing useful >>>>> geoengineering based on this. >>>>> >>>>> It’s interesting that in the Solomon the water vapor increase is noted >>>>> to have gone into a considerable decline around 2000-2003, around a decade >>>>> after Pinatubo. Further, it is important to note that the complex dynamics >>>>> leading to these entangled positive and negative forcings from a single >>>>> pulse will almost certainly be shifted by the sheer act of continuous >>>>> prolongation inherent in geoengineering, so the constant Pinatubo meme >>>>> becomes a little....empty? >>>>> >>>>> Cheers, Nathan >>>>> >>>>> On Tuesday, August 5, 2014 2:38:34 PM UTC-4, kcaldeira wrote: >>>>>> >>>>>> Folks, >>>>>> >>>>>> I am supposed to give a keynote talk at CEC14 in two weeks. For this >>>>>> talk, I would like to try to develop a list of oft-cited memes that many >>>>>> assume are established facts, but which may not in fact be true. >>>>>> >>>>>> I am thinking of things like: "With solar geoengineering, there will >>>>>> be winners and losers." "Termination risk is an important reason not to >>>>>> engage in solar geoengineering." "Solar geoengineering will cause >>>>>> widespread drying." >>>>>> >>>>>> I don't want to discuss all of these things here but simply to >>>>>> develop a list. You could help me by sending an email answering the >>>>>> questions: >>>>>> >>>>>> 2a. What memes are out there which many "experts" regard as >>>>>> well-established facts but which in fact might not be correct? >>>>>> >>>>>> 2b. Why do you suspect the correctness of that meme? >>>>>> >>>>>> 2c. (optional) Can you provide a citation or a link to where someone >>>>>> is assuming the meme is true? >>>>>> >>>>>> Thoughtful responses would be most appreciated. If you want to start >>>>>> discussion about a meme, please do so in a separate thread so that this >>>>>> thread can be easily used to develop a list. >>>>>> >>>>>> Thanks, >>>>>> >>>>>> Ken >>>>>> >>>>>> _______________ >>>>>> 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 >>>>>> https://twitter.com/KenCaldeira >>>>>> >>>>>> Assistant: Dawn Ross <[email protected]> >>>>>> >>>>>> -- >>>>> 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. >>>>> 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 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. 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