Hi guys I have been reading this paper from 2012 by the Royal Society. The global vision and research program fro geoengineering trials - with a view to settling on the most cost effective one - in case of a planetary emergency.
I have shortened it so it is easy to read and get your head around.
Link to whole document at the end.
Lifting options for stratospheric aerosol geoengineering 2012
The Royal Society report ‘Geoengineering the Climate’ identified solar radiation management using albedo-enhancing aerosols injected into the stratosphere as the most affordable and effective option for geoengineering, but did not consider in any detail the options for delivery. This paper provides outline engineering analyses of the options, both for batch-delivery processes, following up on previous work for artillery shells, missiles, aircraft and free-flying balloons, as well as a lengthier analysis of continuous delivery systems that require a pipe connected to the ground and supported at a height of 20 km, either by a tower or by a tethered balloon.
Note:Happening this year over USA, courtesy of David keith
Towers are shown not to be practical, but a tethered balloon delivery system, with high-pressure pumping, appears to have much lower operating and capital costs than all other delivery options. Instead of transporting sulphuric acid mist precursors, such a system could also be used to transport slurries of high refractive index particles such as coated titanium dioxide. The use of such particles would allow useful experiments on opacity, coagulation and atmospheric chemistry at modest rates so as not to perturb regional or global climatic conditions, thus reducing scale-up risks. Criteria for particle choice are discussed, including the need to minimize or prevent ozone destruction. The paper estimates the time scales and relatively modest costs required if a tethered balloon system were to be introduced in a measured way with testing and development work proceeding over three decades, rather than in an emergency. The manufacture of a tether capable of sustaining the high tensions and internal pressures needed, as well as strong winds, is a significant challenge, as is the development of the necessary pumping and dispersion technologies. The greatest challenge may be the manufacture and launch of very large balloons, but means have been identified to significantly reduce the size of such balloons or aerostats.
At an Engineering and Physical Sciences Research Council/Natural Environment Research Council workshop in March 2010, proposals were invited for preliminary research into geoengineering by various methods including solar radiation management (SRM) by particle injection into the stratosphere. At the workshop, the idea of a high-altitude tethered balloon delivery system, with ultra-high pressure pumping to elevate fluids or particle slurries, appeared to offer significant advantages over other delivery options. A proposal to investigate the desired particle properties, the method of their delivery and modelling their impact on the climate was funded. The dispersion at altitude of particles manufactured at ground level, with tailored size distributions and coatings may provide benefits, such as reduced or negligible ozone impact, not readily available to other delivery options. This paper reviews the merits of this idea alongside those of other delivery options.
Previously, Blackstock considered the scientific and engineering requirements of various technologies but did not consider costs. Others have provided cost estimates for certain technologies such as aircraft and naval artillery but did not consider as many delivery options. Consideration has also been given by some of the authors to the use of tethered aerostats, manufactured particles, drag reduction strategies and dispersion technologies. The lead time required for implementation of any injection system is a particularly important criterion if the real value of SRM options is to provide an insurance policy against global warming and its effects.
Manufacture of the particles should be low cost, with a low environmental impact, and the particles must have negligible toxicity. Ideally, there should be a sufficient supply of the relevant raw materials to ensure availability for at least a century. Various high refractive index particle systems could be considered but titanium dioxide (TiO2) is a promising candidate. No other particle comes anywhere close to its properties: it has a high refractive index, its safety has been well researched and it is produced in industrial quantities.
Early experiments could be carried out from free-flying balloons or fast jets, possibly followed in due course with a high-pressure pipe supported from a relatively small (approx. 100 m diameter) balloon. The latter system would be able to create progressively larger plumes at altitude to enable the atmospheric chemistry, dispersion scattering and electrical effects to be studied. Much of the technology to examine such plumes is available from existing atmospheric science studies using satellites, free-flying balloons, aircraft and ground-based equipment.
Notwithstanding all of the above, the use of H2S as a precursor system for sulphuric acid aerosols has the great advantage of generating almost five times the mass of the material lofted, through the supply of oxygen from the stratosphere, i.e. H2S + 2O2 → H2SO4. A particulate system also needs a conveying gaseous material to be lofted. Scattering calculations and process flow analyses indicate that the conveying material mass flow and the extra mass provided by the ‘free oxygen’ are likely to negate mass reduction through higher scattering per unit volume. However, creating an appropriate sulphuric acid mist at altitude in a representative environment poses significant problems. Without that capability, the slowness of the reaction of SO2 to H2SO4 means that local, small-scale experiments would be impossible: atmospheric circulation would disperse precursor material (SO2 or H2S) around the planet before sulphuric acid mists would form, and also before suitable measurements could be carried out on their effects.
A rational comparison of the technologies for delivery of aerosols into the stratosphere must include outline estimates for the financial costs involved. Any such estimates will be based on various assumptions and preconditions.
The concept of using cheap latex balloons, similar to weather balloons, to lift a payload of particles has been considered by a number of authors. The analysis given here closely follows that in COSEPUP but uses different values for some parameters. A 20m diameter balloon has been assumed to be the maximum practicable.
If individual balloons are not reused, one balloon is required per flight. The total cost of hydrogen is £1.4 billion, that of balloon fabric is £4 billion (with fabrication costs on this scale being minimal when compared with material costs), and that of canisters is £1.2 billion per year. These numbers imply a total cost of approximately £7 billion per year.
Compared with the single-use balloon case, the number of balloons required falls if they can be retrieved and reused. However, the cost and environmental impact of retrieving the spent balloons is likely to be significant, and could be greater than for single-use balloons since greater care would be needed in retrieval to ensure reusability.
It is difficult to conceive of any tower option being achievable in the foreseeable future, but they have been proposed and should be considered. Both environmental and social costs can perhaps be considered to be moderate rather than high but would be overwhelmed by the effects of the massive financial investment needed for towers.
Systems based on aircraft have the advantage of using modified military vehicles; they can loiter in the stratosphere long enough to disperse the particles effectively and would be reusable. They have the disadvantage that there would be a significant energy cost in getting to the required height, and there would be a significant modification cost.
Fast jets (F-15)
The F-15 has a maximum payload of around 10 tonnes, so injecting 10 million tonnes of aerosols into the atmosphere requires around a million flights per year. If each plane is capable of performing three 2 h flights per day, or roughly 1000 flights per year, a fleet of 1000 planes should be able to deliver the intended annual payload. The cost per plane is about £25 million. A fleet of 1000 modified planes would therefore incur a total capital cost of £25 billion.
Tanker jets (KC-10 and KC-135)
The analysis is similar to the section above but the maximum altitude the tanker jets can reach is below that needed to get above the tropopause except in polar regions where injection is less effective. The payload of the KC-10 is around 80 tonnes, so with 1000 flights p.a. a total of 125 planes would be required. In 1998, the KC-10unit cost was $88 million, corresponding to a cost today of £70 million or £9 billion for a fleet of 125. At 40 000 flight hours http://www.fas.org/programs/ssp/man/uswpns/air/fighter/f15.html
The largest naval artillery shell that could be fired in the twentieth century weighed 1510 kg using the 18inch (0.457 m) barrel designed for HMS Furious in the First World War]. The size of the gun was effectively limited by the size of the ship needed to support it; the barrel itself weighed 151 tonnes and had a very complex form of construction. Such guns had a muzzle velocity of 738 m s−1 and a horizontal range of about 37 km.
Missiles differ from artillery in that they possess their own means of propulsion and guidance. There is no longer a need for the gun barrels that made up a large proportion of the cost of the artillery option.
‘Battlefield range ballistic missiles’ have a range of 70 km, a weight of 1500 kg and a payload of 500 kg www.fas.org/nuke/guide/pakistan/missile/hatf-1.htm
The cost of missiles can be significantly reduced if individual missiles are reused, in which case they would have to make a controlled landing. They would thus need to be powered after dispersing the payload so might be much more closely based on cruise missiles or a new generation of high performance.
Electrical technology has developed to the extent that it is now feasible to use it to accelerate an object to the speeds needed by weapons. For stratospheric injection, the projectile would not need to be steered, so the system could be a fixed-axis device mounted inside a shaft in the ground, either vertically or, more probably, slightly inclined towards an area where the debris could safely fall.
A railgun can provide energies of the order of 50 MJ and seems feasible for SRM operations in the near future http://www.defenseindustrydaily.com/bae-producing-scaleddown-rail-g...
Coilguns use linear motor technology http://en.wikipedia.org/wiki/Coilgun , By surrounding a tube with a series of annular coils that are switched on and off in sequence, a ferromagnetic projectile can be accelerated.
High altitude airships
Airships have the advantage, over free-flying balloons, of being powered and able (weather permitting) to navigate back to given launch points.
Mixing aerosols into the fuel supplies of commercial flights (sound familiar?)
It has been suggested that sulphur compounds could be added to the fuel on commercial airliners to permit the deployment of albedo enhancing aerosols without needing to expend large amounts of additional energy and resources on specifically constructed aerosol lofting mechanisms
Commercial airliners only reach the stratosphere when flying over the poles. Elsewhere, the tropopause is above normal flight levels. No modifications to the aircraft would be necessary and aerosols could be dispersed as part of jet engine exhaust.
Balloon-supported high-pressure pipes
Pumping precursors to aerosols such as H2S or SO2 via a pipe elevated by a balloon or aerostat or has been suggested by a number of authors. The concept that is described here was developed in 2009 by one of us and n refined with the help of the co-authors: a large high-altitude balloon or aerostat located at around 20 km altitude of sufficient size can provide enough lift to support its own weight as well as the weight of a fibre-reinforced pipe, lifting devices intermittently spaced along the tether, and the weight of the fluid being pumped through the pipe. The balloon system has a low cost and only moderate difficulty of manufacture.
Comparing aerosol delivery technologies
It is now possible to compare the various options for delivering aerosols to the stratosphere. Table 3 shows a comparison of the systems discussed above in purely financial terms; the costs are taken from the discussion made earlier and then a net present cost has been calculated for establishing each technology and operating it for 10 years, taking a discount rate of 5 per cent. Allowing for differences in the injection rate, the costs show good agreement with McClellan et al. for the more limited number of technologies considered in that work, except for the tethered balloon. This difference can be explained by the much larger development costs suggested there, and the greater number of balloon systems.
There may be arguments against SRM of any kind, for instance that it does not directly retard ocean acidification, and there may be arguments against geoengineering itself. But while it is desirable that we work on reducing carbon emissions now, it would be prudent to have emergency systems in reserve as an insurance policy. We should design the emergency mechanism before we need it, so that it can be tested to make sure that it is safe to use. After considering the various options for SRM by stratospheric particle injection, we suggest that a tethered balloon supporting a pressurized pipe is likely to be efficient, practical, controllable and much cheaper than any probable alternative. A tethered balloon system might be used to deliver SRM, not just as an emergency measure, but also as part of a well-moderated and thoughtful process of climate control.
For full pdf with all scientific details and cost analysis go here: http://www2.eng.cam.ac.uk/~hemh1/SPICE/papers/PhilTransRoySoc_Lifti...
Good one Rose. Hopefully he will be recognised for this in the future. I had a giggle yesterday when looking for this document in Google - guess what - the search engine names my 'Short version of lifting options', as number one on search list - a link to this page he he. I hope more people read it - maybe even david
The deliberate stop/start spraying that Ive managed to "see with my own eyes" around here has been by small aircraft. I have no way of judging what height they spray at but it really never seemed that far up.
But I figure the "grey blanket treatment" must be coming from other deployment system, perhaps from those off shore cloud factories we see in the weather radars.
This paper looks to me like them boasting about what they have been perfecting for decades. Madness.