The recent bright water discussions are interesting to me partly as a psychological phenomenon. Just as Seitz begins his paper noting the similarity between hydrosols in water and aerosols in air, with hydrosols having their attendant analogues to the “Twomey effect” – similarly complex issues of their size and their effects on light scattering, etc. – so the bright water story starts to seem like a kind of oceanic parallel of the whole stratospheric sulfur story.
In their joint piece last year reviewing various geoengineering options (in Issues in Science and Technology, 2010), white surfacing was listed by Keith/Caldeira at the very bottom in order of “likelihood of feasibility at large scale” for all SRM approaches, even below satellites in space. Obviously, it was a minor error in their fine review and was partly just grammatical – spreading white paint is surely more ‘feasible’ than putting reflector shields into outer space – but I think it was also partly a reflection of a common reflex: there is a natural desire to find a geoengineering technique that can have the greatest maximum potential impact and gives the greatest bang for the buck, as quickly as possible. Just as aerosol SRM quickly became a cynosure, bright water now is starting to have a similar kind of fascination and buzz – it could have significant maximum potential, sounds initially like it might not be too costly, and it involves physical issues that are notoriously complex, meaning that one can easily keep one’s eye on the extremely simple and highly desired goal – its potential for lots of cheap, quick cooling – but be unable to draw any precise picture of its negatives and thus to compare it accurately to much more modest proposals. Keith/Caldeira surely meant to say that white surfacing is more limited in its maximum potential impacts than the other SRM techniques they discussed, which is true. But it is clearly much more ‘feasible,’ really at the top of feasibility, of all SRM today, in the sense that there are few objections from anyone to doing it right now, it wouldn’t be very costly, could even save people money and give some modest help to the climate through its SRM and its co-benefit of reduced GHG emissions (biochar is in a somewhat analogous position, and wasn’t mentioned). With a Pacala/Socolow-type approach to stabilization of emissions applied to geoengineering techniques, white surfacing could become an important technique within the mix, one we can start with right away, unlike almost all others, and it might be that the impact it can offer safely might not be that small compared to that of aerosols in the end (and its comparative economics might look pretty good, too, if aerosol ‘collateral damage’ remains a problem). Now then, let’s jump into the ocean – there’s bright water in place of aerosols, and there could be floats just like white surfacing. Just as aerosol SRM seems more dicey the closer one looks at it, there might be all kinds of analogous issues involving the mixing of surface waters and their oxygenation, and surely problems involving biotic impacts are likely to be much more thorny with hydrosols than with aerosols. Meanwhile, simple floats are something like the oceanic equivalent of white roofing, and they seem among the least explored here in these discussions. They are low-tech and they aren’t very sexy, but perhaps floats could be designed to be strung together as ‘artifical ice floes’ to be used in previously iced-over areas or somewhat south of the Bering strait, perhaps taking advantage of differing currents to stay held in gyre-like motions, their surfaces above the water except for their ‘legs,’ allowing heat release, and with hanging “side-teeth” to create windbreak, and the tops having a very high albedo, made from recycled plastics. Compared to white roofing, they would have the advantage that once developed they could be placed in areas of great immediate strategic value for the climate, like the ESAS, or south of it. I guess I’m a bit skeptical about the ‘1,000 windmills’ energy cost in the Seitz paper, and perhaps I’m just being completely ignorant, but if I simply try to imagine to myself a given 12’x12’ patch of ocean and trying to keep its albedo raised for the next 20 years by continuously making bubbles there, and then I picture making a float with a very high albedo top out of recycled plastics and letting it just sit there for a couple of decades, it would seem the latter would be energetically much better. With tens of millions of tons of various plastic waste every year, much of it easily reformed into the EPS, etc, out of which docks are often made today, could it really be energetically better to make bubbles that don’t last, that demand constant energy input, involve complex machinery that would have to withstand tough oceanic conditions, and that would have much more complex interactions with oceanic life? But I’m all for doing everything we can, so I truly do hope that bright water gets investigated as fully as possible – and I hope that it works, too – but I also hope that it is not concentrated on here to the exclusion of the more humble and low-tech things, which sometime seem relatively unexplored in these discussions. -- 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]. 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