Dear all, In case you were not aware, the workshop, which was to have been 3-4th September, is now going to be on 15-16th October. Here is the background and purpose of the workshop.
A group of scientists and engineers (including myself) is deeply concerned about the potential of methane from thawing permafrost in the Arctic to cause runaway global warming. Major factors are the unexpectedly rapid retreat of sea ice [1] and the unexpectedly large quantities of carbon which might be emitted as methane [2]. In June 2010 we wrote an open letter to Obama's scientific adviser, Dr John Holdren, suggesting action was urgently needed to address the methane issue [3]. Some sea ice experts, including Professor Peter Wadhams in our group, now reckon the Arctic ocean will very likely become seasonably ice free this decade if there is no action to cool the Arctic. Recently Peter Wadhams has drawn my attention to work of Natalia Shakhova with Igor Semiletov on East Siberian Arctic Shelf (ESAS) - particularly concerning the present large emissions of methane and the possibility of release of much larger quantities "at any time". So we have been wondering whether anything can be done quickly to reduce this methane threat. We have been discussing possible action, and plan further brainstorming at a workshop in October in London. We are hoping this workshop will lead on to a pilot project to trial the most promising techniques. Here is an extract from the proposal, concerning management of the methane environment at the local level (e.g. in ESAS): [begin quote] Approaches can be categorised according to where the intervention action takes place. Where the methane is from lake or sea bed, the action could be: - below the permafrost, where there may already be methane or methane hydrate; - in the permafrost, or to plug gaps in the permafrost where methane is rising; - in the bed of the sea or lake, above the permafrost layer; - in the water at the bottom of the sea or lake; - at the surface of the sea or lake, and below any ice; - at the point of emergence of methane into the atmosphere. In the case of methane from wetlands, some of the above actions would be relevant to ponds, commonly forming above permafrost and emitting most of the wetlands methane. There is also the possibility of pond drainage as a means to reduce methane emissions. Returning to the case of lakes and deeper water, the problem with trying to deal with methane below the permafrost is that any disturbance is liable to trigger an eruption of methane through gaps in permafrost known as taliks. Commercial methods of extraction of natural gas can be used when there is in impermeable layer above the gas, but cannot be applied in our situation because of the danger either from puncture of the permafrost or from enlarging existing taliks. In the bed of the sea or lake there may be aerobic microbes, capable of ‘digesting’ the methane and converting it into less harmful products. Supply of oxygen and nutrients to such microbes could be helpful. Microbes may also congregate in a ‘biotic layer’ at the bottom of the sea or lake. These could be boosted or encouraged to proliferate. Methane can dissolve in the water. At atmospheric pressure and freezing point, 0.04 grams of methane will dissolve in a litre of water. Therefore one approach could be to extract the water when it is nearly saturated with methane. A more commercial approach would be to use a specific methane solvent in a relatively heavy layer, resting on the seabed (or lake bed). From time to time the solvent would be extracted, scrubbed to remove the methane, and replaced. A major issue could be containing the solvent and making sure there was no long-term harm to the marine habitat. A general problem with emissions of soluble gas from the beds of lakes and shallow seas is that the water column can become unstable – with the dissolved gases coming out of solution, leading to a sometime violent upwelling. Because of the low density of the rising column of bubble-filled water, ships on the surface can sink! Furthermore any turnover of the water allows warmer surface water to be transported towards the bottom, which can lead to permafrost melt and enhanced methane production. Thus any underwater approach to methane must take into account the stability of the water column. However if the methane is already bubbling to the surface, then one could consider capturing it before it escapes into the atmosphere. One way would be to use ice, which will anyway be present in winter. The methane collects under the ice, and boring through the ice, one could collect the methane that emerges. The problem would be keeping an intact layer of ice throughout the year. Therefore one might consider strengthening the ice to produce ‘pykrete’ [3]. However a more promising approach would be to have mats, preferably of methane-absorbing substance (biological or chemical) which could be harvested to collect the methane. But care would be needed not to deplete oxygen from water underneath the mats, since oxygen is required from the important methane-digesting microbes in any biotic layer that has formed above the sea or lake bed. If and when some methane bursts into the atmosphere, it could be burnt or ‘flared’. In remote areas, and in open water, this could be problematic. Furthermore, methane only burns in air at between 5% and 15% concentration by volume. As it disperses quickly, one would need to torch the methane within a few seconds of eruption. It is almost impossible to imagine how this could be done in a remote location, unless the methane is laser-zapped from a monitoring satellite! [end quote] The pilot project will promote a three-prong attack, though trials will focus on local action (particular item 2): 1. cooling the Arctic, regionally or locally, using SRM geoengineering; 2. management of the methane environment at the local level (see quoted text above); 3. capture or destruction of methane, already in the atmosphere. The capture or destruction of methane in the atmosphere is a last resort, if other approaches fail. It would also be vital if there were a sudden large emission of methane with serious warming potential. Such "air capture" or destruction could be local or not. The advantage of local air capture is that efficiency may be improved through having the methane at higher concentration (as the efficiency is for CO2 air capture). The workshop is intended as a brainstorming session to establish the most promising techniques which might be trialled in the pilot project. If you have already expressed an interest in attending the workshop, please confirm that the new date is OK. If you have not yet expressed an interest, and would like to attend, let me know. John Nissen Chiswick, London W4 [1] Copenhagen Diagnosis, 2009 http://www.ccrc.unsw.edu.au/Copenhagen/Copenhagen_Diagnosis_LOW.pdf see figure 13 page 30. [2] Ibid, see page 21 - referring to Shuur et al 2008. [3] http://geo-engineering.blogspot.com/2010/06/sea-ice-loss-stuns-scientists.html -- 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.
