Could an artificial volcano cool the planet by dimming the sun?

Could an artificial volcano cool the planet by dimming the sun?















Dimming
the sun by engineering the effects of an artificial volcano is a
feasible and potentially cost-effective option to reduce temperatures
on Earth, a report says.
Dimming
the sun by engineering the effects of an artificial volcano is a
feasible and potentially cost-effective option to reduce temperatures
on Earth, the first major study of the practicality of planetary-scale solar radiation management (SRM) concludes.
The authors, US aerospace company Aurora Flight Sciences, consider the
challenge of lifting and releasing 1-5m tonnes a year of sulphur
dioxide to altitudes approaching 100,000ft. This would create sulphate
particles in the thin air and provide a partial shade to the sun's
rays, potentially reducing temperatures 1-2C. But no attempt is made to
quantify the potential benefits or the risks involved in the likely
disruption of weather patterns on earth.

The easiest, but by far the most expensive, way to launch vast
quantities of sulphur dioxide into the upper atmosphere would be via
batteries of 16-inch naval guns, says the report. But to lift 5m tonnes
of particles a year 100,000ft into the stratosphere might need 70m gun
shots a year and could cost an astronomical $700bn a year. Over 20
years, considered by many scientists the minimum needed to have a
lasting effect on earth, this would be more than Africa and India
together earn in a year.

Instead, the authors consider a far less expensive but technically more
challenging way to lift and disperse 1-5m tonnes of sulphur particles
to around 100,000ft. This would be to design and build a fleet of
massive helium-filled blimps, costing $8-10bn a year to run, with each
blimp costing possibly $500m. However, the technology of airships
operating at this altitude is not developed.

The study, commissioned by the University of Calgary in Canada, was
published 15 months ago but has received little attention so far.
However, it shows how advanced SRM advocates are in their attempts to
persuade governments to license large-scale experiments.

It was managed by the leading geoenegineering Harvard University
scientist David Keith, one of two administrators of Bill Gates's Fund for Innovative Climate and Energy Research (Ficer) which contributed $100,000 to the study.

By far the most effective way to lift the sulphur, the study concludes,
would be to adapt, or to build, a fleet of Boeing 747s aircraft. About
14 of these planes working round the clock from bases on or near the
equator, might cost about $8bn a year.
The study supports the views of scientists who argue that more experiments should be done into geoengineering to prepare a "plan B" if politicians and industry fail to find a way to reduce emissions in climate talks.

"The primary conclusion to draw from this feasibility and cost study is
that geoengineering is feasible from an engineering standpoint and
costs are comparable to quantities spent regularly on large engineering
projects or aerospace operations.
"Aeroplane geoengineering operations are comparable to the yearly
operations of a small airline, and are dwarfed be the operations of a
large airline like FedEx or Southwest," says the study.

Critics of political attempts to reduce emissions have long argued that
it would cost hundreds of billions of dollars of investment in
low-carbon energy to achieve the same results.
To date, the uncertainty and inherent riskiness of large-scale solar radiation management have not been quantified.


Source:-
http://www.guardian.co.uk/environment/blog/2012/feb/06/artificial-volcano-cool-planet-sun