[geo] Re: tropospheric aerosol use
Thanks for the responses - though what I had in mind was actually more in line with the tenor of Mike's latest comments about the 6-to-1 lifetime ratio for arctic sulfur SRM, stratospheric vs. tropospheric, etc. David’s early article is very impressive for how much it adumbrated the current public discourse on geoengineering, though at the same time, a bit of misunderstanding about what I was intending to ask – and I was probably not expressing myself very well – possibly underscores how something really has been shifting lately within the geoengineering world, too. What I meant about tropospheric sulfur injections was entirely in the newer sense of a more ‘localized geoengineering’, which has been getting attention here in this group lately (so much so that I forgot to mention what I meant in my question), and which I think makes a world of difference in considering its use. In a sense, stratospheric injections can’t be effectively localized, and this newer local thinking - coming in response to events on the ground - might bring out new ways of considering tropospheric sulfur versus stratospheric sulfur, as Mike’s comments from earlier today in that other thread show, and the issue of sulfur's dangers, which are the main point in David's comments, are clearly altered by the reduced scale of use. In the BBC article that Andrew has just posted, Pete Wadhams is talking about AMEG’s plans should the methane situation there deteriorate a good deal further (which seems almost certain, if I had to guess), and they focus on MCB alone. I think I had first seen mention here of tropospheric sulfur injections in this context from Mike, and this really took off in my imagination when I by chance shortly afterward saw some work involving Eileen Matthews (Gauci et al) showing how strongly just ordinary levels of acid rain will impede methanogenesis in wetlands, with strong reductions, like 40% or so, which play out through considerably longer time periods than the brief atmospheric lifetime of the aerosols. I think study of this combined methane-SRM effect for tropospheric sulfur injection should really be done. Curiously, David, in what you sent me, the abstract on intercontinental effects of SO2 don’t suggest that Russia is particularly bad for that particular concern, less so than Europe, for example. And curiously, I might add, despite what you just wrote, in your early paper you had actually listed stratospheric injections as more dangerous than tropospheric (although I assume for entirely different reasons, related then to ozone loss concerns, etc). But this is really something very different now from all that, or from Budyko’s early comparisons of efficiency, lifetimes, etc. We’re talking about a very limited area for treatment, almost nothing by comparison with plans to geoengineer a global –1W/m2 or some such thing. And currently one third of the land area of China is experiencing acid rain, I recently read. How could it be acceptable to add copious amounts of sulfur to one of the most densely populated parts of the planet, which will clearly lead to considerable mortality and sickness, and unacceptable to add any sulfur at all to a mostly unpopulated area around the mouth of the Lena river, where there are globally dangerous submarine methane hotspots and lots of wetlands, thermokarst lakes, etc, emitting plenty of methane right nearby? Could one not hope that there might be some effect from the sulfur on the shelf floor itself, too? (I've cc-ed Vincent Gauci on this, and maybe he could easily answer that). After all, it is a complex picture at the ESAS, probably with older methane stores and current methanogenesis from thawing submarine permafrost driving the ambient methane levels' rise there together. Indeed, the isotopic analysis thus far points more to contemporary methane, which might realistically be capable of being impacted – so it might be possible to help push back against this spiraling situation in multiple respects at once simply through tropospheric emissions of sulfur. That is, with pinpointed and targeted ground level injections, there’s the scattering effect – less efficient than in the stratosphere but still certainly present – then the indirect effect (its ‘Twomey’ effect), and then its methane-suppressing effects as well. Someone should try to roughly calculate what might be possible totals in terms of local – RF, given different options for release area, amount of release per hour, estimates of what the wetlands near the hotspots are currently emitting, etc. Further, since it sounds from the BBC article as though MCB is the main thing being considered by AMEG right now, another question of mine would be for John, and that is how would the interaction of such ground-level sulfur injection and the MCB compare to the rather synergistic situation of MCB with stratospheric injections? (I noticed that Wadhams is proposing MCB down around the Diomedes, though). I realize that’s probably
Re: [geo] Source on SRM causing warming
For clarity, I've never used or advocated this 10C figure, just explained where I think it was from. I don't think CCN manipulation in the arctic is expected. From what I understand It's proposed that any local cooling will be at lower latitudes, on water headed to the arctic. It's been pointed out to me that arctic geoengineering alone will risk monsoon failure by moving the ITCZ. Perhaps one of the climatic modelers can confirm? A On Mar 18, 2012 1:29 AM, Mike MacCracken mmacc...@comcast.net wrote: The Robock et al simulations of an Arctic injection found that the lifetime of particles in the lower Arctic stratosphere was only two months. In that one would only need particles up during the sunlit season (say three months, for only really helps after the sea ice surface has melted and the sun is high in the sky). During the relatively calm weather of Arctic summer, the lifetime of tropospheric sulfate, for example—and quite possibly sea salt CCN--emitted above the inversion is likely 10 days or so. It is not at all clear to me that the 6 to 1 or so lifetime advantage of the lower stratosphere is really worth the effort to loft the aerosols. And on the temperature rise in the polar stratosphere, I would hope any calculation of the effects of the sulfate/dust injection only put it in during the sunlit season—obviously, there would be no effect on solar radiation during the polar night, so, with a two month lifetime of aerosols there, it makes absolutely no sense to be lofting anything for about two thirds of the year. And so likely no effect on winter temperatures (although warming the coldest part of the polar winter stratosphere might well help to prevent an ozone hole from forming). So, I think a tropospheric brightening approach is likely the better option. Whether it can be done with just CCN or might also need sulfate seems to me worth investigating (what one needs may well be not just cloud brightening, but also clear sky aerosol loading). Best, Mike * On 3/17/12 8:41 PM, Ken Caldeira kcalde...@carnegie.stanford.edu wrote: That is just misleading. The third attachment is a top-of-atmosphere radiation balance on the email I am responding to shows shortwave radiation. The attached figure shows the corresponding temperature field from the same simulation for the same time period. Note Arctic cooling. Also, we should not focus on individual regional blobs of color in an average of a single decade from a single simulation. The paper these figures came from is here: http://www.atmos-chem-phys.net/10/5999/2010/acp-10-5999-2010.pdf ___ Ken Caldeira Carnegie Institution Dept of Global Ecology 260 Panama Street, Stanford, CA 94305 USA +1 650 704 7212 kcalde...@carnegie.stanford.edu http://dge.stanford.edu/labs/caldeiralab @kencaldeira *YouTube: * http://www.youtube.com/watch?v=a9LaYCbYCxo Climate change and the transition from coal to low-carbon electricity http://www.youtube.com/watch?v=a9LaYCbYCxo Crop yields in a geoengineered climate http://www.youtube.com/watch?v=-0LCXNoIu-c On Sat, Mar 17, 2012 at 1:31 PM, Andrew Lockley and...@andrewlockley.com wrote: Hi Here are some model outputs which Stephen sent me. These appear to show localized arctic warming in geoengineering simulations. This could be due to winter effects. I assume this is the source for the controversial figure in the BBC quote A -- You received this message because you are subscribed to the Google Groups geoengineering group. To post to this group, send email to geoengineering@googlegroups.com. To unsubscribe from this group, send email to geoengineering+unsubscr...@googlegroups.com. For more options, visit this group at http://groups.google.com/group/geoengineering?hl=en.
Re: [geo] Re: We are top story on BBC environmental news
Hi Josh, Before commenting on your question, I need to explain the recent activities of AMEG, a group whose position Professor Salter supports. Professor Peter Wadhams and I gave evidence, on behalf of AMEG, to the first of two hearings of the Environment Audit Committee (AEC) inquiry Protecting the Arctic on 21st February. We were given an opportunity to make a further presentation of the AMEG case to the All-Party Parliamentary Climate Change Group (APPCCG) on 13th March, i.e. last Tuesday, where we were joined by Professor Salter and journalist, Jon Hughes. Richard Black, of the BBC, reported on the APPCCG meeting [1]. The second hearing of EAC was on 14th March, at which the Met Office gave oral evidence, reported by the Guardian [2] [3]. I am a great supporter of Stephen's cloud brightening approach, and we both want it deployed as soon as possible. Stephen is a supporter of Peter Wadhams and the AMEG position, that geoengineering is urgently needed to try to save the sea ice. The sea ice is disappearing extraordinarily rapidly as Richard Black reports from the APPCCG presentation [4] and you can see from the graph of sea ice volume decline [5]. One can see from this graph that, if we are unlucky and the sea ice volume declines this summer as much as it did between the minimum in 2009 and 2010, i.e. ~2000 km-3, then it would halve the sea ice left this September. Such a collapse in volume is likely to be accompanied by a collapse in sea ice extent. With less heat flux going into melting the ice, there could be a sudden spurt in Arctic warming, making a reversal to restore the ice, by geoengineered cooling, extremely difficult if not impossible. A point of no return could be reached this summer. Therefore we are in a desperate situation. As I pointed out to the EAC, beggars can't be choosers, so we have to use available means to try and cool the Arctic quickly, and avoid any actions which could make this daunting task more difficult. Thus for example, we urged EAC to recommend an immediate halting of Arctic drilling because escape of methane (the main constituent of natural gas) would have a warming effect on the Arctic. Stephen was not at the EAC hearing on 21st February, but afterwards made it clear to the committee that he supported the AMEG position. Just before the hearing, the committee had received an email [6] from some geoengineering experts recommending research but suggesting that development and deployment of geoengineering techniques was premature, thus undermining the AMEG position. The signatories had apparently included Stephen Salter, but this was a mistake - he had not agreed to the wording that was used. On the other hand the APPCCG meeting last week was an opportunity for Stephen to trumpet the advantages of cloud brightening over what is seen as its main rival. So I think you should take Stephen's strong statement as a warning that, if used at the wrong time and place, stratospheric aerosols could be counterproductive. I'll let him produce his detailed argument, which he submitted as written evidence to the EAC hearing. We will no doubt have to use a combination of techniques and measures to deal with the desperate situation in the Arctic. Cheers, John [1] http://www.bbc.co.uk/news/science-environment-17400804 [2] http://www.guardian.co.uk/business/2012/mar/14/oil-spill-arctic-exploration [3] http://www.guardian.co.uk/environment/2012/mar/14/met-office-arctic-sea-ice-loss-winter [4] Analysis from the University of Washington, in Seattle, using ice thickness data from submarines and satellites, suggests that Septembers could be ice-free within just a few years. [5] http://neven1.typepad.com/.a/6a0133f03a1e37970b0153920ddd12970b-pitaken from http://neven1.typepad.com/blog/2011/10/piomas-september-2011-volume-record-lower-still.html [6] Email from Hue Coe to members of the AEC, 21st Feb, forwarded to the geoengineering group on 23rd by Andrew Lockley. --- On Sat, Mar 17, 2012 at 5:55 PM, Josh Horton joshuahorton...@gmail.comwrote: The idea of putting dust particles into the stratosphere to reflect sunlight, mimicking the cooling effect of volcanic eruptions, would in fact be disastrous for the Arctic, said Prof Salter, with models showing it would increase temperatures at the pole by perhaps 10C. That's a pretty strong statement--what's the evidence for this? Josh Horton On Saturday, March 17, 2012 6:25:22 AM UTC-4, Andrew Lockley wrote: http://www.bbc.co.uk/news/**science-environment-17400804http://www.bbc.co.uk/news/science-environment-17400804 Climate 'tech fixes' urged for Arctic methane By Richard Black Environment correspondent, BBC News An eminent UK engineer is suggesting building cloud-whitening towers in the Faroe Islands as a technical fix for warming across the Arctic. Scientists told UK MPs this week that the possibility of a major methane release triggered by melting Arctic ice constitutes a planetary
RE: [geo] Re: We are top story on BBC environmental news
Hello John Nissen and All, John N says:- Just before the hearing, the committee had received an email [6] from some geoengineering experts recommending research but suggesting that development and deployment of geoengineering techniques was premature, thus undermining the AMEG position. I was one of the signatories that John alluded to. I believe that each one of us feel it shameful and dangerous that that research into promising SRM ideas has not been significantly financially supported. The major stages of the required research involve modelling, resolution of all technological questions, examination of - and international agreement on - possible adverse consequences of deployment, and the execution of (in the case of MCB, for example), of a limited area field-testing experiment. If the required funding was available now I think I think all the above goals could be achieved in 5 years, perhaps even 3. At the moment these goals are far from being achieved. An attempt to successfully deploy now any likely SRM technique would be doomed to failure. The technological questions have not been fully resolved - so it would not work - and there would be - in my opinion - an international outcry against deployment. We would be shooting ourselves in the foot, I think, if we tried to deploy now. If there was a major failure - which is likely - the response could be such as to prohibit further SRM work for a long time.We need to engage in crash programmes of research now, which means that we need immediately to obtain the required funding. [How, I dont know, I'm afraid]. All Best, John (Latham) John Latham Address: P.O. Box 3000,MMM,NCAR,Boulder,CO 80307-3000 Email: lat...@ucar.edu or john.latha...@manchester.ac.uk Tel: (US-Work) 303-497-8182 or (US-Home) 303-444-2429 or (US-Cell) 303-882-0724 or (UK) 01928-730-002 http://www.mmm.ucar.edu/people/latham From: geoengineering@googlegroups.com [geoengineering@googlegroups.com] on behalf of John Nissen [johnnissen2...@gmail.com] Sent: Sunday, March 18, 2012 12:40 PM To: joshuahorton...@gmail.com Cc: geoengineering; John Nissen; P. Wadhams; Stephen Salter; JON HUGHES; Albert Kallio Subject: Re: [geo] Re: We are top story on BBC environmental news Hi Josh, Before commenting on your question, I need to explain the recent activities of AMEG, a group whose position Professor Salter supports. Professor Peter Wadhams and I gave evidence, on behalf of AMEG, to the first of two hearings of the Environment Audit Committee (AEC) inquiry Protecting the Arctic on 21st February. We were given an opportunity to make a further presentation of the AMEG case to the All-Party Parliamentary Climate Change Group (APPCCG) on 13th March, i.e. last Tuesday, where we were joined by Professor Salter and journalist, Jon Hughes. Richard Black, of the BBC, reported on the APPCCG meeting [1]. The second hearing of EAC was on 14th March, at which the Met Office gave oral evidence, reported by the Guardian [2] [3]. I am a great supporter of Stephen's cloud brightening approach, and we both want it deployed as soon as possible. Stephen is a supporter of Peter Wadhams and the AMEG position, that geoengineering is urgently needed to try to save the sea ice. The sea ice is disappearing extraordinarily rapidly as Richard Black reports from the APPCCG presentation [4] and you can see from the graph of sea ice volume decline [5]. One can see from this graph that, if we are unlucky and the sea ice volume declines this summer as much as it did between the minimum in 2009 and 2010, i.e. ~2000 km-3, then it would halve the sea ice left this September. Such a collapse in volume is likely to be accompanied by a collapse in sea ice extent. With less heat flux going into melting the ice, there could be a sudden spurt in Arctic warming, making a reversal to restore the ice, by geoengineered cooling, extremely difficult if not impossible. A point of no return could be reached this summer. Therefore we are in a desperate situation. As I pointed out to the EAC, beggars can't be choosers, so we have to use available means to try and cool the Arctic quickly, and avoid any actions which could make this daunting task more difficult. Thus for example, we urged EAC to recommend an immediate halting of Arctic drilling because escape of methane (the main constituent of natural gas) would have a warming effect on the Arctic. Stephen was not at the EAC hearing on 21st February, but afterwards made it clear to the committee that he supported the AMEG position. Just before the hearing, the committee had received an email [6] from some geoengineering experts recommending research but suggesting that development and deployment of geoengineering techniques was premature, thus undermining the AMEG position. The signatories had apparently included Stephen Salter, but this was a mistake -
Re: [geo] Re: We are top story on BBC environmental news
Josh My source is figure 2b of Jones Hayward Boucher Kravtitz and Robock of June 2010 in Atmospheric Chemistry and Physics They reckon 5 million tonnes year will do a general world-wide coolling of 1.1 watt/m2 but will work the wrong way over the Arctic giving a warming of 4 to10 watts/m2 above the methane releasing areas where last year there was a step up by a factor of 20. I was caeful to say 10 watts not 10 C but other speakers had been talking in temperature which are already scary enough. Jon Egil Kristjansson at Oslo has some confirming results. Can anyone predict the effects of a spike of methane lasting two years? I will put figure 2b in my next email incase your spam filters disapprove of it. The reason for intense Arctic warming might be that in the summer stratospheric aerosol scatters energy from solar rays that might just have missed the earth and half the scattering is downwards. At the summer solstice there is more solar energy hitting the North pole than the equator. In winter there could be about 200 watts per square metre of longwave radiation trying to get out from the Arctic to deep space. Aerosol at any height cannot tell up from down and will reflect some back like a blanket. Low level cloud brightening would have exactly the same blanketing effect but the shorter life means that we have a much better chance of not getting any salt residues that far north. Intercepting heat going from the tropics to the poles can be done anywhere along the route. Cloud brightening anywhere away from the Arctic will cool it. Short life and local control is a very attractive feature. Patchy and quick good, promiscuous and slow bad. The cloud brightening community would greatly appreciate some distinction between our own low-level highly controlled activities and higher level, uncontrolled more acidic ones. See if there is anything in your spam tray. Stephen Josh Horton wrote: The idea of putting dust particles into the stratosphere to reflect sunlight, mimicking the cooling effect of volcanic eruptions, would in fact be disastrous for the Arctic, said Prof Salter, with models showing it would increase temperatures at the pole by perhaps 10C. That's a pretty strong statement--what's the evidence for this? Josh Horton On Saturday, March 17, 2012 6:25:22 AM UTC-4, Andrew Lockley wrote: http://www.bbc.co.uk/news/science-environment-17400804 Climate 'tech fixes' urged for Arctic methane By Richard Black Environment correspondent, BBC News An eminent UK engineer is suggesting building cloud-whitening towers in the Faroe Islands as a technical fix for warming across the Arctic. Scientists told UK MPs this week that the possibility of a major methane release triggered by melting Arctic ice constitutes a planetary emergency. The Arctic could be sea-ice free each September within a few years. Wave energy pioneer Stephen Salter has shown that pumping seawater sprays into the atmosphere could cool the planet. The Edinburgh University academic has previously suggested whitening clouds using specially-built ships. At a meeting in Westminster organised by the Arctic Methane Emergency Group (Ameg), Prof Salter told MPs that the situation in the Arctic was so serious that ships might take too long. I don't think there's time to do ships for the Arctic now, he said. We'd need a bit of land, in clean air and the right distance north... where you can cool water flowing into the Arctic. Favoured locations would be the Faroes and islands in the Bering Strait, he said. Towers would be constructed, simplified versions of what has been planned for ships. In summer, seawater would be pumped up to the top using some kind of renewable energy, and out through the nozzles that are now being developed at Edinburgh University, which achieve incredibly fine droplet size. In an idea first proposed by US physicist John Latham, the fine droplets of seawater provide nuclei around which water vapour can condense. This makes the average droplet size in the clouds smaller, meaning they appear whiter and reflect more of the Sun's incoming energy back into space, cooling the Earth. On melting ice The area of Arctic Ocean covered by ice each summer has declined significantly over the last few decades as air and sea temperatures have risen. For each of the last four years, the September minimum has seen about two-thirds of the average cover for the years 1979-2000, which is used a baseline. The extent covered at other times of the year has also been shrinking. What more concerns some scientists is the falling volume of ice. Analysis from the University of Washington, in Seattle, using ice thickness data from submarines and satellites, suggests that Septembers could be ice-free within just a few years. Data for September suggests the Arctic Ocean could be free of sea ice in a few years In 2007, the water [off northern
Re: [geo] Source on SRM causing warming
Mike I had thought that the plan was stratospheric aerosol to be released at low latitudes and would slowly migrate to the poles where is would gracefully descend. If you can be sure that it will all have gone in 10 days then my concerns vanish. But if the air cannot get through the water surface how can the aerosol it carries get there? It will form a blanket even if it is a very low one. A short life would mean that we do not have to worry about methane release. But can we do enough to cool the rest of the planet? Perhaps Jon Egil can tell us about blanket lifetime. Stephen Mike MacCracken wrote: The Robock et al simulations of an Arctic injection found that the lifetime of particles in the lower Arctic stratosphere was only two months. In that one would only need particles up during the sunlit season (say three months, for only really helps after the sea ice surface has melted and the sun is high in the sky). During the relatively calm weather of Arctic summer, the lifetime of tropospheric sulfate, for example‹and quite possibly sea salt CCN--emitted above the inversion is likely 10 days or so. It is not at all clear to me that the 6 to 1 or so lifetime advantage of the lower stratosphere is really worth the effort to loft the aerosols. And on the temperature rise in the polar stratosphere, I would hope any calculation of the effects of the sulfate/dust injection only put it in during the sunlit season‹obviously, there would be no effect on solar radiation during the polar night, so, with a two month lifetime of aerosols there, it makes absolutely no sense to be lofting anything for about two thirds of the year. And so likely no effect on winter temperatures (although warming the coldest part of the polar winter stratosphere might well help to prevent an ozone hole from forming). So, I think a tropospheric brightening approach is likely the better option. Whether it can be done with just CCN or might also need sulfate seems to me worth investigating (what one needs may well be not just cloud brightening, but also clear sky aerosol loading). Best, Mike * On 3/17/12 8:41 PM, Ken Caldeira kcalde...@carnegie.stanford.edu wrote: That is just misleading. The third attachment is a top-of-atmosphere radiation balance on the email I am responding to shows shortwave radiation. The attached figure shows the corresponding temperature field from the same simulation for the same time period. Note Arctic cooling. Also, we should not focus on individual regional blobs of color in an average of a single decade from a single simulation. The paper these figures came from is here: http://www.atmos-chem-phys.net/10/5999/2010/acp-10-5999-2010.pdf ___ Ken Caldeira Carnegie Institution Dept of Global Ecology 260 Panama Street, Stanford, CA 94305 USA +1 650 704 7212 kcalde...@carnegie.stanford.edu http://dge.stanford.edu/labs/caldeiralab @kencaldeira YouTube: http://www.youtube.com/watch?v=a9LaYCbYCxo Climate change and the transition from coal to low-carbon electricity http://www.youtube.com/watch?v=a9LaYCbYCxo Crop yields in a geoengineered climate http://www.youtube.com/watch?v=-0LCXNoIu-c On Sat, Mar 17, 2012 at 1:31 PM, Andrew Lockley and...@andrewlockley.com wrote: Hi Here are some model outputs which Stephen sent me. These appear to show localized arctic warming in geoengineering simulations. This could be due to winter effects. I assume this is the source for the controversial figure in the BBC quote A -- The University of Edinburgh is a charitable body, registered in Scotland, with registration number SC005336. -- You received this message because you are subscribed to the Google Groups geoengineering group. To post to this group, send email to geoengineering@googlegroups.com. To unsubscribe from this group, send email to geoengineering+unsubscr...@googlegroups.com. For more options, visit this group at http://groups.google.com/group/geoengineering?hl=en.
Re: [geo] Re: We are top story on BBC environmental news
Dear John, How I wish we had the time. We should have been doing what you suggest immediately after the crash in sea ice extent of September 2007 - a wake-up call. We have just left it far too late, and have no option but to try anything that might reduce the chance of a collapse in sea ice extent this year. If you just look at the PIOMAS graph of sea ice volume which is down 75% in three decades and compare it with the sea ice extent which is down 40%, it is obvious that the sea ice extent cannot hold out much longer while the ice continues thinning. There must be a great deal of heat going into melting the ice - and much of this heat is from the heating of open water by the sun when the sea ice retreats - i.e. from the albedo flip effect. After a collapse such that there's little sea ice left in September, there will be a spurt in Arctic warming, perhaps to double the current rate of warming. And after we have a nearly sea ice free Arctic ocean for six months, the warming could increase to triple or quadruple the current rate. Meanwhile there is the methane to contend with. There are already signs of an escalation of methane emissions from shallow seas of the continental shelf. That by itself would be cause for concern, since the sea ice retreat is allowing the seabed to warm well above the thaw point for methane hydrates. So I have three questions for you: 1. Do you seriously recommend that nobody does anything for at least three years while there is more research into geoengineering? 2. How can you say that geoengineering is doomed to failure? Do you really lack confidence in your own modelling? 3. What do I tell my wife and children if nothing is done and the worst happens? Kind regards, John --- On 18/03/2012 15:29, John Latham wrote: Hello John Nissen and All, John N says:- Just before the hearing, the committee had received an email [6] from some geoengineering experts recommending research but suggesting that development and deployment of geoengineering techniques was premature, thus undermining the AMEG position. I was one of the signatories that John alluded to. I believe that each one of us feel it shameful and dangerous that that research into promising SRM ideas has not been significantly financially supported. The major stages of the required research involve modelling, resolution of all technological questions, examination of - and international agreement on - possible adverse consequences of deployment, and the execution of (in the case of MCB, for example), of a limited area field-testing experiment. If the required funding was available now I think I think all the above goals could be achieved in 5 years, perhaps even 3. At the moment these goals are far from being achieved. An attempt to successfully deploy now any likely SRM technique would be doomed to failure. The technological questions have not been fully resolved - so it would not work - and there would be - in my opinion - an international outcry against deployment. We would be shooting ourselves in the foot, I think, if we tried to deploy now. If there was a major failure - which is likely - the response could be such as to prohibit further SRM work for a long time.We need to engage in crash programmes of research now, which means that we need immediately to obtain the required funding. [How, I dont know, I'm afraid]. All Best, John (Latham) John Latham Address: P.O. Box 3000,MMM,NCAR,Boulder,CO 80307-3000 Email: lat...@ucar.edu or john.latha...@manchester.ac.uk Tel: (US-Work) 303-497-8182 or (US-Home) 303-444-2429 or (US-Cell) 303-882-0724 or (UK) 01928-730-002 http://www.mmm.ucar.edu/people/latham From: geoengineering@googlegroups.com [geoengineering@googlegroups.com] on behalf of John Nissen [johnnissen2...@gmail.com] Sent: Sunday, March 18, 2012 12:40 PM To: joshuahorton...@gmail.com Cc: geoengineering; John Nissen; P. Wadhams; Stephen Salter; JON HUGHES; Albert Kallio Subject: Re: [geo] Re: We are top story on BBC environmental news Hi Josh, Before commenting on your question, I need to explain the recent activities of AMEG, a group whose position Professor Salter supports. Professor Peter Wadhams and I gave evidence, on behalf of AMEG, to the first of two hearings of the Environment Audit Committee (AEC) inquiry Protecting the Arctic on 21st February. We were given an opportunity to make a further presentation of the AMEG case to the All-Party Parliamentary Climate Change Group (APPCCG) on 13th March, i.e. last Tuesday, where we were joined by Professor Salter and journalist, Jon Hughes. Richard Black, of the BBC, reported on the APPCCG meeting [1]. The second hearing of EAC was on 14th March, at which the Met Office gave oral evidence, reported by the Guardian [2] [3]. I am a great supporter of Stephen's cloud brightening approach, and we both want it deployed as soon
RE: [geo] Re: We are top story on BBC environmental news
John Do you have a physically based model that backs up these about collapse and quadrupling of warming rate? If so, please let us see it. If not, please consider either retracting these claims or finding a way to make clear the level of uncertainty involved. We have a climate problem and a public relations problem. The first email I have from you in my archives is dated 2008 and suggests the complete disappearance of summer Arctic sea ice at the by 2013. This now seems highly unlikely. If the current claims about immanent collapse are also proved false (as I expect they will be) you will provide ammunition to those who argue against action. Reality is bad enough. David -Original Message- From: geoengineering@googlegroups.com [mailto:geoengineering@googlegroups.com] On Behalf Of John Nissen Sent: Sunday, March 18, 2012 11:24 AM To: John Latham Cc: johnnissen2...@gmail.com; joshuahorton...@gmail.com; geoengineering; P. Wadhams; Stephen Salter; JON HUGHES; Albert Kallio Subject: Re: [geo] Re: We are top story on BBC environmental news Dear John, How I wish we had the time. We should have been doing what you suggest immediately after the crash in sea ice extent of September 2007 - a wake-up call. We have just left it far too late, and have no option but to try anything that might reduce the chance of a collapse in sea ice extent this year. If you just look at the PIOMAS graph of sea ice volume which is down 75% in three decades and compare it with the sea ice extent which is down 40%, it is obvious that the sea ice extent cannot hold out much longer while the ice continues thinning. There must be a great deal of heat going into melting the ice - and much of this heat is from the heating of open water by the sun when the sea ice retreats - i.e. from the albedo flip effect. After a collapse such that there's little sea ice left in September, there will be a spurt in Arctic warming, perhaps to double the current rate of warming. And after we have a nearly sea ice free Arctic ocean for six months, the warming could increase to triple or quadruple the current rate. Meanwhile there is the methane to contend with. There are already signs of an escalation of methane emissions from shallow seas of the continental shelf. That by itself would be cause for concern, since the sea ice retreat is allowing the seabed to warm well above the thaw point for methane hydrates. So I have three questions for you: 1. Do you seriously recommend that nobody does anything for at least three years while there is more research into geoengineering? 2. How can you say that geoengineering is doomed to failure? Do you really lack confidence in your own modelling? 3. What do I tell my wife and children if nothing is done and the worst happens? Kind regards, John --- On 18/03/2012 15:29, John Latham wrote: Hello John Nissen and All, John N says:- Just before the hearing, the committee had received an email [6] from some geoengineering experts recommending research but suggesting that development and deployment of geoengineering techniques was premature, thus undermining the AMEG position. I was one of the signatories that John alluded to. I believe that each one of us feel it shameful and dangerous that that research into promising SRM ideas has not been significantly financially supported. The major stages of the required research involve modelling, resolution of all technological questions, examination of - and international agreement on - possible adverse consequences of deployment, and the execution of (in the case of MCB, for example), of a limited area field-testing experiment. If the required funding was available now I think I think all the above goals could be achieved in 5 years, perhaps even 3. At the moment these goals are far from being achieved. An attempt to successfully deploy now any likely SRM technique would be doomed to failure. The technological questions have not been fully resolved - so it would not work - and there would be - in my opinion - an international outcry against deployment. We would be shooting ourselves in the foot, I think, if we tried to deploy now. If there was a major failure - which is likely - the response could be such as to prohibit further SRM work for a long time.We need to engage in crash programmes of research now, which means that we need immediately to obtain the required funding. [How, I dont know, I'm afraid]. All Best, John (Latham) John Latham Address: P.O. Box 3000,MMM,NCAR,Boulder,CO 80307-3000 Email: lat...@ucar.edu or john.latha...@manchester.ac.uk Tel: (US-Work) 303-497-8182 or (US-Home) 303-444-2429 or (US-Cell) 303-882-0724 or (UK) 01928-730-002 http://www.mmm.ucar.edu/people/latham From: geoengineering@googlegroups.com [geoengineering@googlegroups.com] on behalf of John Nissen [johnnissen2...@gmail.com]
RE: [geo] Source on SRM causing warming
Steven I am in favor of serious research on both strat aerosols and sea salt CCN. Your comments suggest that you already know the outcome of that research. You may of course be correct, and in many ways I hope you are. I, however, see less basis for certainty. A few facts that seem relevant: 1. All simulations of stratospheric aerosols of which I am aware do show an arctic cooling tendency and increase in sea ice extent. 2. There is little reason to doubt that 1 Wm^2 radiative global forcing could be produce by sulfate aerosols using well understood technologies. (That is not a claim about risks and side effects, just about basic capability.) 3. There are large uncertainties about the efficacy of sea salt CCN in producing radiative forcing. It will certainly work sometimes under some conditions, but we don't yet have a good quantitative understanding of extent of conditions in which it might work and therefore of the aggregate effectiveness. 4. There are advantages and disadvantages to the fact that the sea salt CCN is more patchy. Given this is seems to me hard to conclude that we know the answer yet. Yours, David -Original Message- From: geoengineering@googlegroups.com [mailto:geoengineering@googlegroups.com] On Behalf Of Stephen Salter Sent: Sunday, March 18, 2012 10:52 AM To: mmacc...@comcast.net Cc: Ken Caldeira; Andrew Lockley; Geoengineering; j.e.kristjans...@geo.uio.no Subject: Re: [geo] Source on SRM causing warming Mike I had thought that the plan was stratospheric aerosol to be released at low latitudes and would slowly migrate to the poles where is would gracefully descend. If you can be sure that it will all have gone in 10 days then my concerns vanish. But if the air cannot get through the water surface how can the aerosol it carries get there? It will form a blanket even if it is a very low one. A short life would mean that we do not have to worry about methane release. But can we do enough to cool the rest of the planet? Perhaps Jon Egil can tell us about blanket lifetime. Stephen Mike MacCracken wrote: The Robock et al simulations of an Arctic injection found that the lifetime of particles in the lower Arctic stratosphere was only two months. In that one would only need particles up during the sunlit season (say three months, for only really helps after the sea ice surface has melted and the sun is high in the sky). During the relatively calm weather of Arctic summer, the lifetime of tropospheric sulfate, for example‹and quite possibly sea salt CCN--emitted above the inversion is likely 10 days or so. It is not at all clear to me that the 6 to 1 or so lifetime advantage of the lower stratosphere is really worth the effort to loft the aerosols. And on the temperature rise in the polar stratosphere, I would hope any calculation of the effects of the sulfate/dust injection only put it in during the sunlit season‹obviously, there would be no effect on solar radiation during the polar night, so, with a two month lifetime of aerosols there, it makes absolutely no sense to be lofting anything for about two thirds of the year. And so likely no effect on winter temperatures (although warming the coldest part of the polar winter stratosphere might well help to prevent an ozone hole from forming). So, I think a tropospheric brightening approach is likely the better option. Whether it can be done with just CCN or might also need sulfate seems to me worth investigating (what one needs may well be not just cloud brightening, but also clear sky aerosol loading). Best, Mike * On 3/17/12 8:41 PM, Ken Caldeira kcalde...@carnegie.stanford.edu wrote: That is just misleading. The third attachment is a top-of-atmosphere radiation balance on the email I am responding to shows shortwave radiation. The attached figure shows the corresponding temperature field from the same simulation for the same time period. Note Arctic cooling. Also, we should not focus on individual regional blobs of color in an average of a single decade from a single simulation. The paper these figures came from is here: http://www.atmos-chem-phys.net/10/5999/2010/acp-10-5999-2010.pdf ___ Ken Caldeira Carnegie Institution Dept of Global Ecology 260 Panama Street, Stanford, CA 94305 USA +1 650 704 7212 kcalde...@carnegie.stanford.edu http://dge.stanford.edu/labs/caldeiralab @kencaldeira YouTube: http://www.youtube.com/watch?v=a9LaYCbYCxo Climate change and the transition from coal to low-carbon electricity http://www.youtube.com/watch?v=a9LaYCbYCxo Crop yields in a geoengineered climate http://www.youtube.com/watch?v=-0LCXNoIu-c On Sat, Mar 17, 2012 at 1:31 PM, Andrew Lockley and...@andrewlockley.com wrote: Hi Here are some model outputs which Stephen sent me. These appear to show localized arctic warming in geoengineering simulations. This could be due to
Re: [geo] Re: We are top story on BBC environmental news
I have to agree with David and Ken. Stick to refereed literature if you have something to say, so the idea can be peer reviewed. And don't pretend to talk for all of us to the press, like Salter and Nissen are doing. Alan [On sabbatical for current academic year. The best way to contact me is by email, rob...@envsci.rutgers.edu, or at 732-881-1610 (cell).] Alan Robock, Professor II (Distinguished Professor) Editor, Reviews of Geophysics Director, Meteorology Undergraduate Program Associate Director, Center for Environmental Prediction Department of Environmental SciencesPhone: +1-732-932-9800 x6222 Rutgers University Fax: +1-732-932-8644 14 College Farm Road E-mail: rob...@envsci.rutgers.edu New Brunswick, NJ 08901-8551 USA http://envsci.rutgers.edu/~robock On Mar 18, 2012, at 11:01 AM, David Keith david_ke...@harvard.edu wrote: John Do you have a physically based model that backs up these about collapse and quadrupling of warming rate? If so, please let us see it. If not, please consider either retracting these claims or finding a way to make clear the level of uncertainty involved. We have a climate problem and a public relations problem. The first email I have from you in my archives is dated 2008 and suggests the complete disappearance of summer Arctic sea ice at the by 2013. This now seems highly unlikely. If the current claims about immanent collapse are also proved false (as I expect they will be) you will provide ammunition to those who argue against action. Reality is bad enough. David -Original Message- From: geoengineering@googlegroups.com [mailto:geoengineering@googlegroups.com] On Behalf Of John Nissen Sent: Sunday, March 18, 2012 11:24 AM To: John Latham Cc: johnnissen2...@gmail.com; joshuahorton...@gmail.com; geoengineering; P. Wadhams; Stephen Salter; JON HUGHES; Albert Kallio Subject: Re: [geo] Re: We are top story on BBC environmental news Dear John, How I wish we had the time. We should have been doing what you suggest immediately after the crash in sea ice extent of September 2007 - a wake-up call. We have just left it far too late, and have no option but to try anything that might reduce the chance of a collapse in sea ice extent this year. If you just look at the PIOMAS graph of sea ice volume which is down 75% in three decades and compare it with the sea ice extent which is down 40%, it is obvious that the sea ice extent cannot hold out much longer while the ice continues thinning. There must be a great deal of heat going into melting the ice - and much of this heat is from the heating of open water by the sun when the sea ice retreats - i.e. from the albedo flip effect. After a collapse such that there's little sea ice left in September, there will be a spurt in Arctic warming, perhaps to double the current rate of warming. And after we have a nearly sea ice free Arctic ocean for six months, the warming could increase to triple or quadruple the current rate. Meanwhile there is the methane to contend with. There are already signs of an escalation of methane emissions from shallow seas of the continental shelf. That by itself would be cause for concern, since the sea ice retreat is allowing the seabed to warm well above the thaw point for methane hydrates. So I have three questions for you: 1. Do you seriously recommend that nobody does anything for at least three years while there is more research into geoengineering? 2. How can you say that geoengineering is doomed to failure? Do you really lack confidence in your own modelling? 3. What do I tell my wife and children if nothing is done and the worst happens? Kind regards, John --- On 18/03/2012 15:29, John Latham wrote: Hello John Nissen and All, John N says:- Just before the hearing, the committee had received an email [6] from some geoengineering experts recommending research but suggesting that development and deployment of geoengineering techniques was premature, thus undermining the AMEG position. I was one of the signatories that John alluded to. I believe that each one of us feel it shameful and dangerous that that research into promising SRM ideas has not been significantly financially supported. The major stages of the required research involve modelling, resolution of all technological questions, examination of - and international agreement on - possible adverse consequences of deployment, and the execution of (in the case of MCB, for example), of a limited area field-testing experiment. If the required funding was available now I think I think all the above goals could be achieved in 5 years, perhaps even 3. At the moment these goals are far from being achieved. An attempt to successfully deploy now any likely SRM technique would be doomed to failure. The technological
RE: [geo] Re: We are top story on BBC environmental news
John (N) Taking yr 3 questions:- 1. Do you seriously recommend that nobody does anything for at least three years while there is more research into geoengineering? Performing research is not doing nothing. It is a vital component of the total effort (as is fund-raising, unfortunately) and must precede deployment. This includes assessments of adverse consequences, seeking international agreement and field-testing the idea. Not to follow this route could SLOW DOWN geo-eng drastically, as argued earlier. 2. How can you say that geoengineering is doomed to failure? Do you really lack confidence in your own modelling? I did not say that, John. I said that I am not aware of any SRM scheme that has been optimally and exhaustively studied in the way defined above, and is therefore ready for deployment. In the case of MCB, we do not yet have a fully functioning spray production system. Our work on adverse consequences is far from completion.etc. Our modelling work provides us with encouragement to continue. 3. What do I tell my wife and children if nothing is done and the worst happens? I suppose you could say that you issued warnings which were not listened to sufficiently. I could not. All of us are trying to help avoid the scenario you pose. It is healthy for us to fight, try to persuade, allow oneself to be persuaded. I may be completely wrong, John, but I think that the people who agree with you have - in some instances - a different interpretation of the scientific facts, or the completeness or general validity of them than people who do not.. If so, with time and tolerance, it should be possible to reach concerted agreement. You might like to know that we have initiated computational studies of the possible role of MCB in inhibiting coral bleaching. Should the work turn out to be potentially valuable, the required field-testing of the idea need only be on a small spatial scale. All Best, John (L). John Latham Address: P.O. Box 3000,MMM,NCAR,Boulder,CO 80307-3000 Email: lat...@ucar.edu or john.latha...@manchester.ac.uk Tel: (US-Work) 303-497-8182 or (US-Home) 303-444-2429 or (US-Cell) 303-882-0724 or (UK) 01928-730-002 http://www.mmm.ucar.edu/people/latham From: John Nissen [j...@cloudworld.co.uk] Sent: Sunday, March 18, 2012 5:23 PM To: John Latham Cc: johnnissen2...@gmail.com; joshuahorton...@gmail.com; geoengineering; P. Wadhams; Stephen Salter; JON HUGHES; Albert Kallio Subject: Re: [geo] Re: We are top story on BBC environmental news Dear John, How I wish we had the time. We should have been doing what you suggest immediately after the crash in sea ice extent of September 2007 - a wake-up call. We have just left it far too late, and have no option but to try anything that might reduce the chance of a collapse in sea ice extent this year. If you just look at the PIOMAS graph of sea ice volume which is down 75% in three decades and compare it with the sea ice extent which is down 40%, it is obvious that the sea ice extent cannot hold out much longer while the ice continues thinning. There must be a great deal of heat going into melting the ice - and much of this heat is from the heating of open water by the sun when the sea ice retreats - i.e. from the albedo flip effect. After a collapse such that there's little sea ice left in September, there will be a spurt in Arctic warming, perhaps to double the current rate of warming. And after we have a nearly sea ice free Arctic ocean for six months, the warming could increase to triple or quadruple the current rate. Meanwhile there is the methane to contend with. There are already signs of an escalation of methane emissions from shallow seas of the continental shelf. That by itself would be cause for concern, since the sea ice retreat is allowing the seabed to warm well above the thaw point for methane hydrates. So I have three questions for you: 1. Do you seriously recommend that nobody does anything for at least three years while there is more research into geoengineering? 2. How can you say that geoengineering is doomed to failure? Do you really lack confidence in your own modelling? 3. What do I tell my wife and children if nothing is done and the worst happens? Kind regards, John --- On 18/03/2012 15:29, John Latham wrote: Hello John Nissen and All, John N says:- Just before the hearing, the committee had received an email [6] from some geoengineering experts recommending research but suggesting that development and deployment of geoengineering techniques was premature, thus undermining the AMEG position. I was one of the signatories that John alluded to. I believe that each one of us feel it shameful and dangerous that that research into promising SRM ideas has not been significantly financially supported. The major stages of the required research involve modelling, resolution of all technological questions, examination
[geo] Re: Stoat strongly criticises AMEG
I'm with Stoat, Ken Caldeira, David Keith, Alan Robock and others who see this emergency effort to rush cloud intervention in the Arctic on behalf of sea ice (and indirectly seabed methane) as undermining the case for a serious push on geo-engineering options, impacts and policy issues. You're getting headlines and the attention of factions in Parliament now, but just wait until the variability kicks the other way. Yelling fire on a hot planethttp://www.nytimes.com/2006/04/23/weekinreview/23revkin.html?_r=2can have unanticipated consequences. -- You received this message because you are subscribed to the Google Groups geoengineering group. To view this discussion on the web visit https://groups.google.com/d/msg/geoengineering/-/UjkE-JJNII0J. To post to this group, send email to geoengineering@googlegroups.com. To unsubscribe from this group, send email to geoengineering+unsubscr...@googlegroups.com. For more options, visit this group at http://groups.google.com/group/geoengineering?hl=en.
[geo] Geoengineering company news
http://motherboard.vice.com/2012/3/18/what-if-we-could-just-suck-all-those-greenhouse-gases-out-of-the-atmosphere--2 In the year 2012, with the two biggest greenhouse gas creators in the world (the U.S. and China, of course) unwilling to do much of anything to cut emissions, we’re basically light years and an autocratic world government away from staving off catostrophic climate change through reductions. So, that leaves us with the ignoble options of just dealing with the rising sea levels and extreme weather and famines etc. as they come or, maybe just maybe, digging our way out with some new technology. Civilization at large deals with — or ignores — problems via this latter mindset more than it would like to admit. Meet Kilamanjaro Air, a tech startup in the would-be business of capturing and selling carbon dioxide, e.g. closing the carbon cycle. The science is essentially the same as that used on submarines and spaceships to scrub CO2 from the air, albeit writ very large. Writer Mark Gunther, a contributing editor at Fortune, details the history Kilimanjaro in a new e-book called Suck It Up, excerpted at the “Ecomagination” blog. (Ecomagination is a blog apparently run by GE, of nuclear weapons engineering, railway locomotive, and 30 Rock fame, so let’s help ourselves to some grains of salt.) Anyhow: The company stumbled at first. As Lackner explained it to me, air capture is a multi-step process —a chemical absorbent first has to bind with CO2, after which the CO2 needs to be separated from the absorbent and compressed into a liquid to be sold or stored. “The hard part is getting the CO2 back off,” he said. GRT’s first absorbent was sodium hydroxide, which effectively captured CO2. But the bond between them was so strong that separating the CO2 required a great deal of energy. In 2007, after testing other absorbents, GRT had devised a new air-extraction technology that uses a plastic resin that bonds with CO2 when dry and gives it back when wet. This was hailed as a breakthrough in a company press release quoting, among others, Jeffrey Sachs, the director of the Earth Institute at Columbia. “This significant achievement holds incredible promise in the fight against climate change,” Sachs said. “Thanks to the ingenuity of GRT and Klaus Lackner, the world may, sooner rather than later, have an important tool in this fight.” It would be later rather than sooner. In 2008, Wright was replaced as CEO by William “Billy” Gridley, an investor in the firm and a former managing director at Goldman Sachs. Kilimanjaro has a staff of 12 working on prototype machines that “catch” C02 via large flat filters via an absorbent and then, once captured, release the C02 and concentrate it into liquid form, where it can be used as fuel (more dirty fuel and then only after being converted to carbon monoxide). I can’t find anything on Kilimanjaro’s website about the machine’s efficiency, which would seem to be a primary limiting factor of the technology. (If it costs more energy to produce a lesser amount of energy, that’s kind of a slim victory.) It’s addressed a very little bit below: Because greenhouse gases are dispersed around the globe, they can be extracted from the air anywhere. Carbon dioxide spewing from a tailpipe in Sao Paulo or a coal plant in China can be captured by a machine in Iceland or the Middle East because the atmosphere functions as a conveyor belt, moving CO2 from its sources to any sink. That’s important because while we can envision a world where most or all of the electricity we use comes from nuclear, solar or wind energy, or from fossil fuels where the CO2 is captured at the power plant, it’s harder to see how emissions from cars, trucks, trains, ships and planes can be eliminated. The beauty of air capture, Lackner and his colleagues explained, is that “one could collect CO2 after the fact and from any source….One would not have to wait for the phasing out of existing infrastructure before addressing the greenhouse gas problem.” Air capture plants, they wrote, could be located atop the best underground reservoirs for storing CO2, which may be in isolated locations. This fact is key to the business plans of all the air-capture startups. In only one regard was Lackner’s paper clearly mistaken —he estimated that the cost of air capture would be “on the order of $10 to $15 per ton,” a target that now looks wildly optimistic. Actually, what’s even more wildly optimistic is the widespread, worldwide deployment of a new industry based upon the harvesting and sale of enriched carbon dioxide any time before we’re living on a pseudo-Venus. While I’m sure Gunther and anyone involved in Kilamanjaro would argue that this technology isn’t meant as a stand-alone solution — though the title Suck It Up kinda suggests otherwise —and there needs to be reductions as well, one can’t help but think diversions like this are just that — less about addressing the problem than addressing our anxiety about the
Re: [geo] Source on SRM causing warming
Hi Stephen--My wording must have been confusing. For stratospheric injections at low latitudes, the lifetime is 1-2 years. The aerosols do move poleward and are carried into the troposphere in mid and high latitudes. This is one approach to trying to limit global climate change, and, as David Keith says, studies indicate that these cool the polar regions, though perhaps not in the stratosphere. Your cloud brightening approach is also to limit global warming. I'd also suggest that we could offset some of the global warming by sulfate aerosols out over vast ocean areas instead of sulfate's present dominance over, now, southeastern Asia, China, etc.--so keeping or modestly enhancing the present cooling offset. [And reducing cirrus may also be a viable approach.] A third approach is to cool the poles (and this might be good for regional purposes alone), but cooling also pulls heat out of lower latitudes and helps to cool them somewhat. The Caldeira-Wood shows it works conceptually (they reduced solar constant) and Robock et al. injected SO2 into stratosphere to do (but the full year injection of SO2/SO4 likely spread some to lower latitudes and the monsoons were affected). One thing Robock et al. found was that the lifetime of sulfate in the polar stratosphere is about two months, and so that means that the potential 100 to 1 advantage of stratospheric sulfate is not valid, and we're down to 6 to 1 compared to surface-based approaches such as CCN or microbubbles to cool incoming waters, sulfate or something similar over Arctic area, surface brightening by microbubbles, etc.--noting that such approaches are only needed (and effective) for the few months per year when the Sun is well up in the sky. As David Keith also says, there is a lot of research to be done to determine which approaches or alone or in different variants might work, or be effective or ineffective and have unintended consequences, much less how such an approach or set of approaches might be integrated with mitigation, adaptation, suffering, etc. Best, Mike MacCracken On 3/18/12 12:52 PM, Stephen Salter s.sal...@ed.ac.uk wrote: Mike I had thought that the plan was stratospheric aerosol to be released at low latitudes and would slowly migrate to the poles where is would gracefully descend. If you can be sure that it will all have gone in 10 days then my concerns vanish. But if the air cannot get through the water surface how can the aerosol it carries get there? It will form a blanket even if it is a very low one. A short life would mean that we do not have to worry about methane release. But can we do enough to cool the rest of the planet? Perhaps Jon Egil can tell us about blanket lifetime. Stephen Mike MacCracken wrote: The Robock et al simulations of an Arctic injection found that the lifetime of particles in the lower Arctic stratosphere was only two months. In that one would only need particles up during the sunlit season (say three months, for only really helps after the sea ice surface has melted and the sun is high in the sky). During the relatively calm weather of Arctic summer, the lifetime of tropospheric sulfate, for example‹and quite possibly sea salt CCN--emitted above the inversion is likely 10 days or so. It is not at all clear to me that the 6 to 1 or so lifetime advantage of the lower stratosphere is really worth the effort to loft the aerosols. And on the temperature rise in the polar stratosphere, I would hope any calculation of the effects of the sulfate/dust injection only put it in during the sunlit season‹obviously, there would be no effect on solar radiation during the polar night, so, with a two month lifetime of aerosols there, it makes absolutely no sense to be lofting anything for about two thirds of the year. And so likely no effect on winter temperatures (although warming the coldest part of the polar winter stratosphere might well help to prevent an ozone hole from forming). So, I think a tropospheric brightening approach is likely the better option. Whether it can be done with just CCN or might also need sulfate seems to me worth investigating (what one needs may well be not just cloud brightening, but also clear sky aerosol loading). Best, Mike * On 3/17/12 8:41 PM, Ken Caldeira kcalde...@carnegie.stanford.edu wrote: That is just misleading. The third attachment is a top-of-atmosphere radiation balance on the email I am responding to shows shortwave radiation. The attached figure shows the corresponding temperature field from the same simulation for the same time period. Note Arctic cooling. Also, we should not focus on individual regional blobs of color in an average of a single decade from a single simulation. The paper these figures came from is here: http://www.atmos-chem-phys.net/10/5999/2010/acp-10-5999-2010.pdf ___ Ken Caldeira Carnegie Institution Dept of Global Ecology 260 Panama
Re: [geo] Re: Stoat strongly criticises AMEG
Just to note, however, that we really do not have a good sense of how big or small variability can be at this melting trend continues‹variability is very unlikely, in my view to be much of a saving influence on the decadal scale unless some strong cooling influence results‹whether from a major volcanic eruption, lots more sulfate pollution on the global scale, or climate engineering. With world warming, it is hard to have the Arctic go very far or very long in the opposite direction. Mike MacCracken On 3/18/12 3:43 PM, Andy Revkin rev...@gmail.com wrote: I'm with Stoat, Ken Caldeira, David Keith, Alan Robock and others who see this emergency effort to rush cloud intervention in the Arctic on behalf of sea ice (and indirectly seabed methane) as undermining the case for a serious push on geo-engineering options, impacts and policy issues. You're getting headlines and the attention of factions in Parliament now, but just wait until the variability kicks the other way. Yelling fire on a hot planet http://www.nytimes.com/2006/04/23/weekinreview/23revkin.html?_r=2 can have unanticipated consequences. -- You received this message because you are subscribed to the Google Groups geoengineering group. To post to this group, send email to geoengineering@googlegroups.com. To unsubscribe from this group, send email to geoengineering+unsubscr...@googlegroups.com. For more options, visit this group at http://groups.google.com/group/geoengineering?hl=en.
[geo] Re: Stoat strongly criticises AMEG
May I make the reminder that their group is not called the Arctic Sea Ice Emergency Group, but the Arctic Methane Emergency Group? The primary issue in all this is: what is happening with arctic methane emissions right now. That's what matters here. Criticizing PIOMAS or whatever is what Al Gore made into effectively exploding fish in the newest version of his slideshow - red herrings. Connelley's blog hardly addresses methane, and nor do these various posts either, to a degree that is, frankly, a little odd. For the record, if I were in the group and asked my opinion of them, I'd recommend against the sea ice loss statements in question, in part because even if the ice losses evolved as predicted, it could end up being more as a consequence and not as a driver. That is, methane increases and sea ice losses are looped, but in complex ways, and the group makes it sound as though it's a one-way street, sea ice loss leading to more methane releases. It should hardly be controversial to say that if there ARE really major methane releases there that the paper Ken attached will no longer be relevant. And thus far the news on the ground makes AMEG seem like quite a rational enterprise, since from what we know it looks relatively probable (much more than so than anyone should be complacent about) that there are rapidly increasing methane excursions going on there. The thing that really matters here for AMEG in terms of expertise and credibility is what Shakhova and Semiletov have been finding in the ESAS region. They are there again right now, and what they see is what will be important. Those wishing to critique the legitimacy of their group should really have things to add to the discussion about those methane releases. Best, Nathan On Mar 18, 3:43 pm, Andrew Revkin rev...@gmail.com wrote: I'm with Stoat, Ken Caldeira, David Keith, Alan Robock and others who see this emergency effort to rush cloud intervention in the Arctic on behalf of sea ice (and indirectly seabed methane) as undermining the case for a serious push on geo-engineering options, impacts and policy issues. You're getting headlines and the attention of factions in Parliament now, but just wait until the variability kicks the other way. Yelling fire on a hot planethttp://www.nytimes.com/2006/04/23/weekinreview/23revkin.html?_r=2can have unanticipated consequences. -- You received this message because you are subscribed to the Google Groups geoengineering group. To post to this group, send email to geoengineering@googlegroups.com. To unsubscribe from this group, send email to geoengineering+unsubscr...@googlegroups.com. For more options, visit this group at http://groups.google.com/group/geoengineering?hl=en.
