An Update on Engineering Issues Concerning Stratospheric Aerosol
Injection for Geoengineering
Abstract
Solar Radiation Management (SRM) geoengineering is a proposed response
to anthropogenic global warming (AGW)1. Stratospheric aerosol injection
(SAI) is one proposed method, reliant on lofting particles into the
stratosphere. Engineering reviews related to this technology approach
have been sparse, with most major primary analyses now at least five
years old. We attempt to bridge this gap – with a short, mainly
qualitative review of recent developments in fields of engineering with
potential applicability to stratospheric aerosol injection. Our analysis
shows that a new conventional aircraft design is still likely to be the
most dependable and affordable technology solution, with hybrid airships
a potential challenger. Rockets, gas guns and MAGLEV/coilguns show some
potential, although they lack the level flight capability preferred for
direct aerosol distribution, without substantial additional engineering.
Should very high-altitude access be required, rockets, hybrid rockets,
and light-gas guns offer the required capability. Costs and performance
for tethered balloons remain highly uncertain. No other methods are
found to be promising. Nevertheless, the extreme accessibility of
disposable balloons suggests that this method may be used primarily for
reasons of political leverage, as opposed to being an optimal
engineering solution.