I’ve just been following the group for a couple of weeks now. A few thoughts:
1. First, taking up on Mike’s previous discussion (Hi, Mike) of a localized use of SRM for the arctic, I am wondering about the following (perhaps you’ve already discussed this, apologies if so): a possible complication seems to me that you could potentially get improved surface temperature and ice cover as desired, but still have rapid destabilization of shelf submarine methane hydrates continuing on, relatively unabated, for quite some time, depending on its precise dynamics. Maslowski’s modelling is generally driven by a lot of warm water getting in at the Bering Strait, which seems logical enough, and might explain the hydrate changes, but some imagine a geothermal cause, and there’s lots of riverine inflow, too, and warmer water coming in via Fram Strait/Barents Sea as well. It would seem important to figure out what is happening with all that, and then, if Maslowski were right, let’s say, it could help to extend the area of injection down into the north pacific (or perhaps some other element to a ‘mixed plan’ could be added to grapple with the problem). Anyhow, doesn’t it seem possible that although the shelf is very shallow, changing what’s happening at the surface alone might not be extremely effective for this part of the problem (and a chief raison d’etre for urgent action to begin with) if warm water is directly spilling into the shelf area through lower currents that remain unchanged. Or am I wrong, and is this not a significant concern? 2. On a ‘soft’ geoengineering note, I organized some testing at UVA on TiO2 activity on methane. We have found that it is possible to photocatalytically activate methane in ambient conditions with TiO2, but it is quite a weak reaction, and we do not think it is really usable as it is. I’m now looking at a possible co-catalyst (Mo is my prime interest). The lab at UVA (Lehmann lab) has great precision in reading methane (to ppt level), but not a lot of expertise with something like calcination of new catalysts, etc. If anyone knows of some lab that might like to help – we would provide detailed experimentals (from an early Graetzel paper), which would be easy stuff for many labs. Of course, TiO2 ‘environmental coatings’ work very well on VOCs, NOx, etc., as they are – but since those have opposing signs, it seems to me that it would have little net effect on RF, even if healthy for the air. The idea would be to get something with -RF that could be added to the surface of the white roof projects, etc. The TiO2 coatings have self-cleansing properties, and so should help boost the reflective surface as well, and on those grounds alone the idea of adding such coatings is already spreading. Perhaps altering the TiO2 catalyst so it is just more selective for NMVOC (but not NOx) would be an alternate route? It wouldn’t save the world, but it could be something practical that would be very likely (I’d guess close to 100%, since such coatings are probably going to be added in any case) to actually get done soon if it could be developed. Any thoughts? 3. In the opposite direction, looking at much more highly invasive measures, here’s a different idea, which I haven’t heard before, and which I only mention with that sense that a ‘think tank’ is all about a willingness to say stupid things! So, forgive me: I remember once talking to a researcher who works on arctic halogen chemistry, who mentioned to me that the reaction of atomic chlorine with methane is some 60x greater than hydroxyl’s. While I know that this might seem like a rather ‘insensitive,’ imagine in the equatorial tropopause, where methane is prevalent and thus somewhat longer lived, some kind of aircraft (or perhaps balloon-based) spraying of ∙Cl over the marine environment. The very strong reaction, Cl+CH4→ClH+CH3 means that hydrochloric acid would be the chief polluting product (the methyl radical would have gotten made eventually in methane hydroxylation), which is apparently a not insignificant part of sea-salt induced rain anyhow (a total deposition of 1.8-5 Tg/yr of nssHCl is estimated, I’ve read). I’m sure there would likely be plenty of other unwanted products, though. Some would surely get up to the stratosphere, but the ozone layer is less affected there, and that at least still has a negative forcing. One might say that if you took a low multiple of natural HCl level as a tolerated pollution limit – say a doubling or tripling of natural levels – then the amount of methane that could be reacted in making that much HCl might be considered ‘safe.’Any thoughts? 4. I know many people have at times suggested various marine floating things – I remember David Keith mentioning somewhere that oceanic reflective particles were in the very first U.S. government- commissioned study mentioning geoengineering, some 40 years ago. But for helping arctic ice, has there been research yet on things like the following? EPS and polyethylene are so abundant in landfills, and so buoyant. Imagine something with four legs (made of EPS coated in polyethylene), and then a polyethylene body staying a couple feet above the water surface, say 12 ft sq., or as large as could be structurally sound, with a reflective (white EPS) surface. It could have some kind of intermittent siding as wind-breaker. Thus it would allow heat dissipation, provide shade for the surface, reflect sunlight, and break the wind. It would not pollute the water much, since the body would be suspended. While it would be quite motile, might it not, where situations were near criticality, help ice creation/survival? Maybe placed in the southern Beaufort Sea, or just north of the Bering Strait, such a thing could prove strategically helpful? Yesterday, Ken’s response 'C.' on the ETC Group report got Josh to say that the “either/or” problems of moral hazard in geoengineering should be solved by the “wedge” concept, both in the sense of including geoengineering in the mix (of course, white roofing, hopcalite catalysts on car radiators, etc, mean it already is, albeit quietly) and within the geoengineering domain itself – i.e., a wide portfolio of different modest-sized possible geoengineering projects would be best. I strongly support that viewpoint. I would think that a goal for modeling would be to design a program to show at any time what the currently agreed to patchwork of emissions reductions will provide, how many Wm-2 we will likely need by when in excess of that, and then be able to show different options for getting there through a variety of pathways. -- You received this message because you are subscribed to the Google Groups "geoengineering" group. To post to this group, send email to [email protected]. To unsubscribe from this group, send email to [email protected]. For more options, visit this group at http://groups.google.com/group/geoengineering?hl=en.
