As various people have noticed, some interesting new patent filings from 2008 have just become public. They pretty clearly flow from brainstorming at a meeting of Intellectual Ventures, Nathan Myhrvold’s innovation [cornucopia|extortion racket] and deal with cooling the surface layers of the ocean by pumping warm surface water below the thermocline. The interesting thing to note is that as well as Nathan and various people who, following Gladwell, I think of as his regular crew — patent lawyer Casey Tegreene, Rod Hyde and Lowell Wood and some other Livermore people — the names on the patent applications include Ken Caldeira, John Latham, Stephen Salter and William H. Gates III. Ken (with whom, I should say as disclosure, I am actually working on something at the moment) is, along with David Keith and possibly Alan Robock, the academic researcher currently most associated with geoengineering discussions. John Latham has championed the possibility of cooling the earth by increasing the reflectivity of marine clouds, and his collaborator Stephen Salter has designed hardware that might do the job (their approach was the focus of my article in Nature this May, as well as many many more by other hands). You probably don’t need me to tell you who William H. Gates III is. He’s half the couple whose Foundation may end up having saved more people than were killed by Stalin, Hitler and Mao.
The main patent application, filed through a company called Searete LLC, describes something a bit like a floating paddling pool with a long pipe dangling down from its centre. Because there will be waves outside the pool but not inside, water will splash in over its edge but not out, and so the water level inside the pool is higher than the level outside the pool. (It strikes me that the motive force here might be treatable as a macroscopic analogue of the Casimir force, but I will leave that for Phil Ball to puzzle over.) That difference in levels — the head — does not have to be very large in order to overcome the buoyancy of the warm surface water and drive it down through the pipe to the cooler depths. Thus heat is taken out of the surface layers. Since high surface temperatures are crucial to the formation of hurricanes, a flotilla of such systems acting to cool potentially-hurricane forming waters in the mid-Atlantic might stop the hurricanes actually getting going, or divert hurricanes moving in from elsewhere.
Cooling surface waters to this end has been suggested before: a company called Atmocean has in fact built prototype systems which aim to do it in almost exactly the opposite way to the Searete patents, by using wave power to pump cool water up instead of sending warm water down. And as Atmocean and others have pointed out, if you can make such a system work there could be more global applications than stopping hurricanes. If you pump warm water down, you will be encouraging cold water to come up, and that cold water will contain nutrients. Lifting nutrients up from the dark depths to the lighter shallows is a way to encourage more photosynthetic growth. More photosynthetic growth might mean more net productivity — and thus more carbon dioxide turned into organic carbon and sequestered. In a 2007 correspondence in Nature, Jim Lovelock and Chris Rapley suggested that pumping up nutrients from the depths this way might be investigated as a geoengineering tool (here’s my blog entry on it from the time). And the Searete patent specifically covers just such geoengineering applications:
A system for altering an aqueous environment, comprising: an application of at least one vessel capable of moving water to lower depths in the water via wave induced downwelling; a system for determining the placement of the at least one vessel based on the application; and a system for placing the at least one vessel in the determined placement … wherein the application includes atmospheric modification … [and] climate modification.
For a fuller description not couched in the barbarous language of patent applications, have a look at Stephen Salter’s submission (pdf) to the recent National Academies panel on geoengineering. This work, which describes itself as funded by Intellectual Ventures, discusses a system 100m wide which has an array of one-way valves that let wave water in but not out, a more efficient and subtler way of doing things than just having some of the water slop over the top (though also one which carries the risks of having many moving parts). A typically neat Salter touch is to have it largely made out of used tyres and concrete. According to his calculations, one such piece of kit could transfer heat out of the surface ocean at a rate of 20GW, which is very impressive (though not in itself much of a match for hurricanes, which dissipate heat at a rate of tens or even hundreds of terawatts, I believe). He also discusses various ways that the hurricane-defusing pumps might encourage carbon-dioxide uptake. I was struck by a neat idea of Ken Caldeira’s: the system might be fine tuned to inject nutrients not into surface waters but into the bottom of the photic zone — the lowest waters at which photosynthesis is possible. It might be the case that increasing photosynthesis at deep levels like this, rather than at the surface as iron-fertilization experiments do, could have advantages in terms of the amount of biomass that ends up sequestered in the deeps.
None of this, I have to say, looks particularly practical or convincing. Jeff Masters at Wunderblog points to some generic problems with hurricane elimination/diversion/modification schemes — a raft of which, he points out, are under examination as part of a Department of Homeland Security project called HURRMIT, which grew out of this meeting in Colorado last year and in which Danny Rosenfeld, who also has an interest in geoengineering, seems to be playing a role. (Here are some associated subsequent presentations from a meeting of the American Meteorological Society). As Masters says, a major issue is that once you try and do something about a hurricane you may well end up getting sued for any damage that hurricane ends up doing, on the basis that if you hadn’t meddled the hurricane might have played out differently. And I suspect it would be very hard to show that such a system worked without trying it out at full scale, which is to say spending billions.
As for the geoengineering application, various people had cogent criticisms of the Lovelock and Rapley idea, including Peter Williams of Bangor and John Shepherd of Southampton, who chaired the Royal Society report on geoengineering heading off to the printers this week and being released in September. But this application does at least have the advantage of being testable on small scales in a way that hurricane diversion simply isn’t. David Karl and colleagues have already tried testing the Atmocean pumps to see if they can produce a double bloom of the sort that Karl’s theories about nitrogen availability would predict. The preliminary results were not very helpful, though: there wasn’t enough shiptime and the pump they deployed broke down:
The “keel” designed by Atmocean was structurally insufficient, and welds of reinforcing material around connection points were also insufficient…The single pump that was recovered showed multiple signs of failure, most notably the tarp tube system that was used…The couplers designed by Atmocean also proved to be insufficient in terms of strength and weld integrity.
In this respect I imagine the no-moving-parts approach described in the Myhrvold et al would be a significant improvement.
The most significant thing about the patent, though, at least for the moment, is not necessarily how good the system is at achieving various goals. It’s the appearance of Gates’s name, which may be his first public demonstration of an interest in geoengineering technologies. Such an interest is hardly a surprise: if you were spectacularly wealthy, concerned for human well being, technologically minded and had a track record of intervention on a world-historic scale, wouldn’t you be interested in at least looking at such technologies? For my part I don’t find that interest unwelcome, either. But I can see it is the sort of interest one could imagine wanting to keep quiet. Some of the many anxieties about geoengineering, after all, focus on what David Victor has called the “Greenfinger” scenario of the billionaire geoengineer going it alone, and this is the sort of thing that could stoke such fears. One to watch.
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