Aurora Flight Sciences recommends Aurora Flight Sciences. At least that’s what David Keith, Climate Professor at the University of Calgary and a leading expert on geoengineering leads to suspect in their joint cost analysis, published three weeks ago.
Keith examines different options to transport one megaton of aerosols per year to a sufficient height for effective cooling. Comparing anything from rockets to guns, to slurry pipelines and 747s, Keith finds the best thing to do would be to design and build special new aircrafts or airships (depending on desired altitude) for the job. It would be cheapest: 1,000,000 tonnes of sulphuric aerosols could be delivered in a range between 40,000 and 100,000 foot or 12-30 kilometres for no more than 2 billion dollars. Using aircraft, limited to the lower third of the altitude range, would be cheapest, perhaps even halving total costs, compared to specially designed high-altitude airships. (The latter may be vulnerable to turbulence when crossing the jet stream, the paper states.)
To return to the science of the matter: both SO2 and H2SO4 would be suited. Cooling for 1 Mt of sulphuric aerosols per year would be close to 1 Watt per square meter*. That would imply James Hansen’s Christmas carol costs only 2 billion dollars. Per year that is. For ever. Roughly speaking, with the failure of Copenhagen having significantly increased the costs of climate policy, between 2010 and 2020 that would, theoretically, be about [please only interpret this as an order of magnitude] 50 times cheaper than the UNFCCC route, recently estimated by the IEA at 1 trillion dollars over the next decade [and probably a lot less expensive beyond 2020, simply maintaing the 450 ppm scenario].
If this were actually true it could mean the deathblow to the world’s oceans, as it competes to the point of completely undermining acidification abating policy – or what used to be referred to as climate mitigation by carbon emissions reductions.
[*This would compensate about two thirds of the current warming, which lies somewhere close to 1.5 W/m2.]
© Rolf Schuttenhelm | www.bitsofscience.org