[geo] Deep ocean disposal
Hi All I used to think that if gas fields had not leaked their natural gas then they should not leak CO2 but I can now see that this argument would be changed by fracking. However if the pressure is high enough the density of CO2 is higher than that of sea water. If you fill a deep sea depression with it and then cover the CO2 puddle with a material which prevents or greatly slows diffusion of CO2 to the sea water then most of it should stay put. The cover could be a layer of liquid with a density intermediate between the CO2 and sea water and very low miscibility with both. This would allow it to self repair. We could also stab pipes through it to add more CO2 of to release some in order to offset Lowell Wood's overdue ice age. We need to look for deep depressions close to where CO2 is being produce or could be concentrated. I did suggest this in a previous contribution to the blog quite a while ago but I think that it sank without trace. This is what we want for the CO2. Stephen Emeritus Professor of Engineering Design Institute for Energy Systems School of Engineering Mayfield Road University of Edinburgh EH9 3JL Scotland Tel +44 131 650 5704 Mobile 07795 203 195 www.see.ed.ac.uk/~shs On 01/06/2011 21:35, Gregory Benford wrote: Michael raises the crucial issue: /*Should the oil and gas industry be relied upon at the geological time scale needed for massive CO2 sequestration? */There are measurements Sherry Rowland told me about ~5 years ago, made by his group at UCI, of the methane content of air across Texas Oklahoma. /He found no difference in methane levels in cities vs oil fields and farms. / He inferred that many oil wells, including spot drillings that yielded no oil, but penetrated fairly deeply, were leaking methane into the air. No one has contradicted this. That made me forget CCS in such domes. Thus I went back to working on CROPS, where we know it takes ~1000 years to return to the atmosphere. Gregory Benford On Wed, Jun 1, 2011 at 1:25 PM, Michael Hayes voglerl...@gmail.com mailto:voglerl...@gmail.com wrote: Hi Folks, After reading Greg's post, I have spent some time looking into the methane release being caused by Fracking. Here is a link to a resent film on the subject. http://www.youtube.com/watch?v=dZe1AeH0Qz8 If you are interested in the methane issue in general, I encourage you to take the time to view this film. I do realize that any media based documentary is subject to dispute and debate. However, I bring this to the group for 2 reasons. 1) These are the same oil fields that are being proposed for massive CO2 geological storage. Fracking is rapidly taking that option off the table. I have never believed oil field CO2 sequestration was practical. However, this type of information should raise profound questions about the entire concept of geological CO2 sequestration. 2) The methane release (GHG effect) from such wide spread use of this drilling method can equal all other anthropogenic GHG sources at the regional level. Fracking is a methane wild card which can not be ignored. And, oil field CO2 sequestration is in direct opposition to the current oil and gas industry activities. I believe the question of; /*Should the oil and gas industry be relied upon at the geological time scale needed for massive CO2 sequestration?*/, should be asked. The issue of fracking related pollution is important and should not be ignored. However, the issue of paying this industry to provided centuries of massive CO2 sequestration should be viewed with skeptical eyes usually reserved for used car salesmen. I do apologize to all used car salesmen for the comparison. Thanks for your patience. Michael -- 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/-/NGdwcTZVTVBhVkFK. To post to this group, send email to geoengineering@googlegroups.com mailto:geoengineering@googlegroups.com. To unsubscribe from this group, send email to geoengineering+unsubscr...@googlegroups.com mailto:geoengineering%2bunsubscr...@googlegroups.com. For more options, visit this group at http://groups.google.com/group/geoengineering?hl=en. -- 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. 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
RE: [geo] Re: Speaking of methane...
This summary review of MMV for CO2 injection by Sue Hovorka may be helpful. http://www.beg.utexas.edu/gccc/bookshelf/Final%20Papers/06-01-Final.pdf From: geoengineering@googlegroups.com [mailto:geoengineering@googlegroups.com] On Behalf Of Michael Hayes Sent: Wednesday, June 01, 2011 6:43 PM To: andrew.lock...@gmail.com Cc: Mike MacCracken; Geoengineering Subject: Re: [geo] Re: Speaking of methane... Tracer use would be the only way to assure we get what we pay for. The only practical way to find a CO2 leak in an oil field would be to see the sand kicking up around the leak. Well head monitoring will not be a reliable means as CO2 can be absorbed into some rock formations. So, any leak related drop in pressure could be readily explained away. Fracking uses chemicals which would leave any clathrate area devoid of life for centuriesif not longer. Calthrate drilling needs hot water which, may itself, have significant effects on the local AOM community as most hydrates are associated with loose sediment. The seepage of the chemicals/hot water would be difficult to control for. Here are 2 papers I base my views upon as they give a detailed view of what is known about the physical reality of the hydrate fields. http://escholarship.org/uc/item/01k4m30p http://escholarship.org/uc/item/2tz8x1ct I have spent most of the last week studying their works and will try to pull together some observations in the next few days. The main point that grabbed my attention was the call for an engineered release to study what may be expected by a GW induced event. Thanks, On Wed, Jun 1, 2011 at 2:48 PM, Andrew Lockley andrew.lock...@gmail.com wrote: It would be nice if that were the case, but even in heavily populated regions such as the Niger delta, where energy infrastructure is extensive and sea ports are accessible, gas flaring is still common. Much methane released is in low concentrations, and can't be recovered, even if the will is there. The oxidisers used for cleaning it out of mine air are serious bits of kit, not installed lightly by operators. Substantial incentives are needed. On another note, can fracking technology be used to dissociate clathrates? A On 1 Jun 2011 22:31, Mike MacCracken mmacc...@comcast.net wrote: I think it is also important to remember the difference. Every reasonable effort will be made to capture any methane they can as it can be sold as energy. The same is not true of CO2, and with the higher background, leaks may well be harder to detect unless some tracer is added to the sequestered CO2. Mike MacCracken On 6/1/11 4:39 PM, Andrew Lockley andrew.lock...@gmail.com wrote: I quite like fracking because it gets the oil industry to fund lots of extremely expensive geoengineering research for us, and the only harm is a load of methane and the odd earthquake. Seems like a fair trade off to me! Obviously, it's a completely unacceptable technique for oil extraction in its current form. Nice data set, though. Shame it doesn't bode well for CCS, though - although I'm sure views may vary. If only we could get the oil industry to build us some cloud machines and high altitude planes... A On 1 Jun 2011 21:25, Michael Hayes voglerl...@gmail.com wrote: Hi Folks, After reading Greg's post, I have spent some time looking into the methane release being caused by Fracking. Here is a link to a resent film on the subject. http://www.youtube.com/watch?v=dZe1AeH0Qz8 If you are interested in the methane issue in general, I encourage you to take the time to view this film. I do realize that any media based documentary is subject to dispute and debate. However, I bring this to the group for 2 reasons. 1) These are the same oil fields that are being proposed for massive CO2 geological storage. Fracking is rapidly taking that option off the table. I have never believed oil field CO2 sequestration was practical. However, this type of information should raise profound questions about the entire concept of geological CO2 sequestration. 2) The methane release (GHG effect) from such wide spread use of this drilling method can equal all other anthropogenic GHG sources at the regional level. Fracking is a methane wild card which can not be ignored. And, oil field CO2 sequestration is in direct opposition to the current oil and gas industry activities. I believe the question of; *Should the oil and gas industry be relied upon at the geological time scale needed for massive CO2 sequestration?*, should be asked. The issue of fracking related pollution is important and should not be ignored. However, the issue of paying this industry to provided centuries of massive CO2 sequestration should be viewed with skeptical eyes usually reserved for used car salesmen. I do apologize to all used car salesmen for the comparison. Thanks for your patience.
Re: [geo] Deep ocean disposal
But aren¹t deep ocean trenches generally subduction zones, so subject to rather massive earthquakes, as recently occurred off Japan? Mike On 6/2/11 5:42 AM, Stephen Salter s.sal...@ed.ac.uk wrote: Hi All I used to think that if gas fields had not leaked their natural gas then they should not leak CO2 but I can now see that this argument would be changed by fracking. However if the pressure is high enough the density of CO2 is higher than that of sea water. If you fill a deep sea depression with it and then cover the CO2 puddle with a material which prevents or greatly slows diffusion of CO2 to the sea water then most of it should stay put. The cover could be a layer of liquid with a density intermediate between the CO2 and sea water and very low miscibility with both. This would allow it to self repair. We could also stab pipes through it to add more CO2 of to release some in order to offset Lowell Wood's overdue ice age. We need to look for deep depressions close to where CO2 is being produce or could be concentrated. I did suggest this in a previous contribution to the blog quite a while ago but I think that it sank without trace. This is what we want for the CO2. Stephen Emeritus Professor of Engineering Design Institute for Energy Systems School of Engineering Mayfield Road University of Edinburgh EH9 3JL Scotland Tel +44 131 650 5704 Mobile 07795 203 195 www.see.ed.ac.uk/~shs http://www.see.ed.ac.uk/~shs On 01/06/2011 21:35, Gregory Benford wrote: Michael raises the crucial issue: Should the oil and gas industry be relied upon at the geological time scale needed for massive CO2 sequestration? There are measurements Sherry Rowland told me about ~5 years ago, made by his group at UCI, of the methane content of air across Texas Oklahoma. He found no difference in methane levels in cities vs oil fields and farms. He inferred that many oil wells, including spot drillings that yielded no oil, but penetrated fairly deeply, were leaking methane into the air. No one has contradicted this. That made me forget CCS in such domes. Thus I went back to working on CROPS, where we know it takes ~1000 years to return to the atmosphere. Gregory Benford On Wed, Jun 1, 2011 at 1:25 PM, Michael Hayes voglerl...@gmail.com wrote: Hi Folks, After reading Greg's post, I have spent some time looking into the methane release being caused by Fracking. Here is a link to a resent film on the subject. http://www.youtube.com/watch?v=dZe1AeH0Qz8 If you are interested in the methane issue in general, I encourage you to take the time to view this film. I do realize that any media based documentary is subject to dispute and debate. However, I bring this to the group for 2 reasons. 1) These are the same oil fields that are being proposed for massive CO2 geological storage. Fracking is rapidly taking that option off the table. I have never believed oil field CO2 sequestration was practical. However, this type of information should raise profound questions about the entire concept of geological CO2 sequestration. 2) The methane release (GHG effect) from such wide spread use of this drilling method can equal all other anthropogenic GHG sources at the regional level. Fracking is a methane wild card which can not be ignored. And, oil field CO2 sequestration is in direct opposition to the current oil and gas industry activities. I believe the question of; Should the oil and gas industry be relied upon at the geological time scale needed for massive CO2 sequestration?, should be asked. The issue of fracking related pollution is important and should not be ignored. However, the issue of paying this industry to provided centuries of massive CO2 sequestration should be viewed with skeptical eyes usually reserved for used car salesmen. I do apologize to all used car salesmen for the comparison. Thanks for your patience. Michael -- 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/-/NGdwcTZVTVBhVkFK. To post to this group, send email to geoengineering@googlegroups.com. To unsubscribe from this group, send email to geoengineering+unsubscr...@googlegroups.com mailto:geoengineering%2bunsubscr...@googlegroups.com . For more options, visit this group at http://groups.google.com/group/geoengineering?hl=en. -- 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
[geo] Methane calculations and Workshop September 3-4
Hi Sam, I agree with your analysis. It is a terrifying prospect with the East Siberian Arctic Shelf (ESAS) in such a critical state [1] (see [2] from 2007 for background). We do have a real emergency. This is why I have instigated a brainstorming workshop on September 3rd and 4th in London, to see if there is any way to stop the methane. I am copying to the whole geoengineering group, so that people know about it. I hope this workshop will spark off a number of projects, tackling the methane problem in various ways: by cooling the region and critical areas, by dealing with the methane in situ, and by 'air capture' of methane that does escape into the atmosphere (if we are too slow with the other approaches). I am also hoping that this workshop will be the start of a privately-funded pilot project, to test out some of the techniques and work out what needs to be done for their full-scale deployment. Meanwhile, let's continue brainstorming here, on the geoengineering list. And, as Andrew has requested on the list, please draw in more people onto the list - anybody who could help - so we can tackle the problem from all angles and pool all ideas. We must not lose hope. Cheers, John [1] http://www.google.co.uk/url?sa=tsource=webcd=4ved=0CCwQFjADurl=http%3A%2F%2Fwww.nioz.nl%2Fpublic%2Fsymposia_workshops%2Farctic%2F17_semiletov.pdfrct=jq=shakhova%20%22methane%20release%20from%20the%20east%22ei=v6fnTfHrH8-z8QPxtKTiCgusg=AFQjCNG3vHHqcRJMHecZrW9GYhX66LkgKgcad=rja [2] http://earth.usc.edu/ftp/lund/BERING%20SEA%20EXP%20323/Uservol/Articles%20of%20interest/Eurasian%20Basin/Shakova%20and%20Semiletov%202007.pdf --- On 02/06/2011 02:29, Sam Carana wrote: Thanks, John, I agree that 40 seems conservative. In my calculations, using a GWP for methane of 105 over 20 years, the 3.5Gt of methane that Shakova observed being released now annually in ESAS would have a greenhouse effect equivalent to 367.5 Pg of CO2. By comparison, the entire rise in CO2 between 1850 and 2000 was 174 PgC, i.e. not even half what the ESAS methane appears to be adding now annually. In fact, Arctic warming resulting from these methane releases will be even worse, since all that methane is initially concentrated in the Artic, whereas GWP for greenhouse gases is typically calculated under the assumption that the respective greenhouse gas is spread out globally. The terrifying prospect is that, due to local concentration of methane and depletion of hydroxyl and oxygen, things will get a lot worse. Initially, much of the methane is oxidized in the sea by oxygen and in the atmosphere by hydroxyls. Over time, however, large methane releases will cause oxygen and hydroxyl depletion, resulting in ever more methane entering the atmosphere and remaining there for a longer period without getting oxidized. As said, this methane will initially be concentrated in the arctic, causing huge Arctic amplification of the greenhouse effect in summer, when the sun doesn't set, heating up the sea and causing further depletion of oxygen (as algae start to bloom) and further accelerating the permafrost melt and thus causing further releases from permafrost and clathrates. I hope that there are some errors somewhere in the above (please email or change the knols if you can improve them), but I fear the situation is quite desperate. Cheers! Sam Carana On Thu, Jun 2, 2011 at 8:22 AM, John Nissenj...@cloudworld.co.uk wrote: Hi Sam, 1. My mistake! Thanks for pointing out my error of 2*280 which should be 2*390 for double C already in atmosphere [1]. I may have made another big error, as I thought global warming potential was molecule for molecule, and comparing volumes at the same pressure. But it's defined as gram for gram. So the 1 gram of methane has 72 times the effect of 1 gram of CO2 over 20 years. This means that 44 ppm of CH4 of molecular weight 16 (=12+4) has 72 times effect of 16 ppm of CO2 of molecular weight 44 (=12+16+16). So 1 ppm of CH4 has 72*16/44 effect of 1 ppm of CO2. I'm not sure how this affects my calculation, so I'll start again from scratch. Using weights rather than ppm or ppb, there is, you say, 750 Gt of carbon currently in atmosphere corresponding to 390 ppm of CO2, giving about 540 Gt when it was 280 ppm. Thus about 210 Gt has been added, which is causing 1.6 W/m-2 of climate forcing. The ESAS has at least 1300 Gt according to Semiletov et al [1]. But let's take the Copenhagen Diagnosis figure of 1672 Gt. This is nearly 8 times more carbon than the 210 Gt added to the atmosphere by humans. Warming effect is near 8*72 = 576 times stronger over 20 years. 10% of this gives factor of 57.6 - over 50 anyway. So 40 was conservative. 50*1.6 = 80 W/m-2 of climate forcing. 2. Your mistake!! In your knol [1], you say: It makes sense to assume that 10% of the carbon stored in permafrost may be released in future. After all, 10% of 1672 Gt is 16.72 Gt. The amount of methane being
[geo] Re: Deep ocean disposal
Michael writes in an earlier email that These are the same oil fields that are being proposed for massive CO2 geological storage. Fracking is rapidly taking that option off the table. I know a little about CCS but not much about fracking - if this is a zero-sum game then we've got a problem. Oil/gas, coal, and power plants do not neatly overlap, so if fracking comes at the expense of CCS, we could see conflicting interests within the broader resource extraction industry. Josh Horton joshuahorton...@gmail.com On Jun 2, 1:10 pm, Stephen Salter s.sal...@ed.ac.uk wrote: Mike We could be picky about our trenches. We do not have to be all that deep, only about 700 metres. Stephen Emeritus Professor of Engineering Design Institute for Energy Systems School of Engineering Mayfield Road University of Edinburgh EH9 3JL Scotland Tel +44 131 650 5704 Mobile 07795 203 195www.see.ed.ac.uk/~shs On 02/06/2011 17:00, Mike MacCracken wrote: But aren't deep ocean trenches generally subduction zones, so subject to rather massive earthquakes, as recently occurred off Japan? Mike On 6/2/11 5:42 AM, Stephen Salter s.sal...@ed.ac.uk wrote: Hi All I used to think that if gas fields had not leaked their natural gas then they should not leak CO2 but I can now see that this argument would be changed by fracking. However if the pressure is high enough the density of CO2 is higher than that of sea water. If you fill a deep sea depression with it and then cover the CO2 puddle with a material which prevents or greatly slows diffusion of CO2 to the sea water then most of it should stay put. The cover could be a layer of liquid with a density intermediate between the CO2 and sea water and very low miscibility with both. This would allow it to self repair. We could also stab pipes through it to add more CO2 of to release some in order to offset Lowell Wood's overdue ice age. We need to look for deep depressions close to where CO2 is being produce or could be concentrated. I did suggest this in a previous contribution to the blog quite a while ago but I think that it sank without trace. This is what we want for the CO2. Stephen Emeritus Professor of Engineering Design Institute for Energy Systems School of Engineering Mayfield Road University of Edinburgh EH9 3JL Scotland Tel +44 131 650 5704 Mobile 07795 203 195 www.see.ed.ac.uk/~shshttp://www.see.ed.ac.uk/~shs http://www.see.ed.ac.uk/%7Eshs On 01/06/2011 21:35, Gregory Benford wrote: Michael raises the crucial issue: */Should the oil and gas industry be relied upon at the geological time scale needed for massive CO2 sequestration? /*There are measurements Sherry Rowland told me about ~5 years ago, made by his group at UCI, of the methane content of air across Texas Oklahoma. /He found no difference in methane levels in cities vs oil fields and farms. / He inferred that many oil wells, including spot drillings that yielded no oil, but penetrated fairly deeply, were leaking methane into the air. No one has contradicted this. That made me forget CCS in such domes. Thus I went back to working on CROPS, where we know it takes ~1000 years to return to the atmosphere. Gregory Benford On Wed, Jun 1, 2011 at 1:25 PM, Michael Hayes voglerl...@gmail.com wrote: Hi Folks, After reading Greg's post, I have spent some time looking into the methane release being caused by Fracking. Here is a link to a resent film on the subject. http://www.youtube.com/watch?v=dZe1AeH0Qz8If you are interested in the methane issue in general, I encourage you to take the time to view this film. I do realize that any media based documentary is subject to dispute and debate. However, I bring this to the group for 2 reasons. 1) These are the same oil fields that are being proposed for massive CO2 geological storage. Fracking is rapidly taking that option off the table. I have never believed oil field CO2 sequestration was practical. However, this type of information should raise profound questions about the entire concept of geological CO2 sequestration. 2) The methane release (GHG effect) from such wide spread use of this drilling method can equal all other anthropogenic GHG sources at the regional level. Fracking is a methane wild card which can not be ignored. And, oil field CO2 sequestration is in direct opposition to
Re: [geo] Re: Deep ocean disposal
It's not that simple. This issue was covered at the royal society. If reserves are deep enough, they will be kept stable by pressure. As long as they're not perturbed and don't diffuse into anything, you should be ok. If you're relying on pressure containment, then fracking is a problem. However, the pressure reservoir is unstable anyway so why use it. Use a deep saline aquifer instead. I don't trust deep ocean disposal as there's no seal. The ocean is too dynamic to mess with in this way. Doesn't pass the gut feel test. Maybe that's voodoo engineering, but it's served me pretty well. Only useful as an emergency option, but the storage isn't the hard bit, as I see it. A On 2 Jun 2011 20:18, Josh Horton joshuahorton...@gmail.com wrote: Michael writes in an earlier email that These are the same oil fields that are being proposed for massive CO2 geological storage. Fracking is rapidly taking that option off the table. I know a little about CCS but not much about fracking - if this is a zero-sum game then we've got a problem. Oil/gas, coal, and power plants do not neatly overlap, so if fracking comes at the expense of CCS, we could see conflicting interests within the broader resource extraction industry. Josh Horton joshuahorton...@gmail.com On Jun 2, 1:10 pm, Stephen Salter s.sal...@ed.ac.uk wrote: Mike We could be picky about our trenches. We do not have to be all that deep, only about 700 metres. Stephen Emeritus Professor of Engineering Design Institute for Energy Systems School of Engineering Mayfield Road University of Edinburgh EH9 3JL Scotland Tel +44 131 650 5704 Mobile 07795 203 195www.see.ed.ac.uk/~shs On 02/06/2011 17:00, Mike MacCracken wrote: But aren't deep ocean trenches generally subduction zones, so subject to rather massive earthquakes, as recently occurred off Japan? Mike On 6/2/11 5:42 AM, Stephen Salter s.sal...@ed.ac.uk wrote: Hi All I used to think that if gas fields had not leaked their natural gas then they should not leak CO2 but I can now see that this argument would be changed by fracking. However if the pressure is high enough the density of CO2 is higher than that of sea water. If you fill a deep sea depression with it and then cover the CO2 puddle with a material which prevents or greatly slows diffusion of CO2 to the sea water then most of it should stay put. The cover could be a layer of liquid with a density intermediate between the CO2 and sea water and very low miscibility with both. This would allow it to self repair. We could also stab pipes through it to add more CO2 of to release some in order to offset Lowell Wood's overdue ice age. We need to look for deep depressions close to where CO2 is being produce or could be concentrated. I did suggest this in a previous contribution to the blog quite a while ago but I think that it sank without trace. This is what we want for the CO2. Stephen Emeritus Professor of Engineering Design Institute for Energy Systems School of Engineering Mayfield Road University of Edinburgh EH9 3JL Scotland Tel +44 131 650 5704 Mobile 07795 203 195 www.see.ed.ac.uk/~shshttp://www.see.ed.ac.uk/~shs http://www.see.ed.ac.uk/%7Eshs On 01/06/2011 21:35, Gregory Benford wrote: Michael raises the crucial issue: */Should the oil and gas industry be relied upon at the geological time scale needed for massive CO2 sequestration? /*There are measurements Sherry Rowland told me about ~5 years ago, made by his group at UCI, of the methane content of air across Texas Oklahoma. /He found no difference in methane levels in cities vs oil fields and farms. / He inferred that many oil wells, including spot drillings that yielded no oil, but penetrated fairly deeply, were leaking methane into the air. No one has contradicted this. That made me forget CCS in such domes. Thus I went back to working on CROPS, where we know it takes ~1000 years to return to the atmosphere. Gregory Benford On Wed, Jun 1, 2011 at 1:25 PM, Michael Hayes voglerl...@gmail.com wrote: Hi Folks, After reading Greg's post, I have spent some time looking into the methane release being caused by Fracking. Here is a link to a resent film on the subject. http://www.youtube.com/watch?v=dZe1AeH0Qz8If you are interested in the methane issue in general, I encourage you to take the time to view this film. I do realize that any media based documentary is subject to dispute and debate. However, I bring this to the group for 2 reasons. 1) These
[geo] Fracking earthquake
I am not sure this made it to the list, so just to make sure. http://www.bbc.co.uk/go/rss/int/news/-/news/uk-england-lancashire-13599161 -- 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.
