Scientists are proposing an unproven way to tackle climate change by spraying sun-dimming chemicals into the Earth’s atmosphere.
A technique known as stratospheric aerosol injection (SAI) could cut the rate of global warming in half, they say.
The research was led by scientists at Harvard and Yale universities and published in the journal Environmental Research Letters.
The idea would involve spraying large amounts of sulphate particles into the Earth’s lower stratosphere at altitudes as high as 12 miles.
The scientists say they will deliver the sulphates with specially designed high-altitude aircraft, balloons or large naval-style guns.
The report does, however, acknowledge that the technique is purely hypothetical right now.
There is no existing technology or aircraft suitable for adaptation but the team say the system could be created in 15 years time.
They say they are ‘developing a new, purpose-built tanker with ‘substantial payload capabilities’ and would neither be ‘technologically difficult nor prohibitively expensive.’
The cost of launching the SAI system is estimated at £2.7 billion ($3.5 bn) with running costs of £1.7 billion ($2.25 bn) a year.
‘We make no judgment about the desirability of SAI,’ the report states.
‘We simply show that a hypothetical deployment program commencing 15 years hence, while both highly uncertain and ambitious, would indeed be technically possible from an engineering perspective. It would also be remarkably inexpensive.’
The team acknowledge that there would be extreme risks with the hypothetical system.
Coordination between multiple countries in both hemispheres would be required.
Aside from that they say the SAI techniques could jeopardise agriculture, lead to droughts or cause extreme weather.
Dr Gergot Wagner from Harvard University’s School of Engineering and co-author of the study said: ‘Given the potential benefits of halving average projected increases in radiative forcing from a particular date onward, these numbers invoke the ”incredible economics” of solar geoengineering.
‘Dozens of countries could fund such a program, and the required technology is not particularly exotic.’
