In an effort to limit the effects of climate change in coming decades, some scientists are advocating a novel approach: injecting the Earth’s atmosphere with sun-dimming chemicals.
The research by scientists at Harvard and Yale universities, published in the journal Environmental Research Letters, proposes using a technique known as stratospheric aerosol injection, which they say could cut the rate of global warming in half.
The technique would involve spraying large amounts of sulfate particles into the Earth's lower stratosphere at altitudes as high as 12 miles. The scientists propose delivering the sulfates with specially designed high-altitude aircraft, balloons or large naval-style guns.
Despite the technology being undeveloped and with no existing aircraft suitable for adaptation, the researchers say that "developing a new, purpose-built tanker with substantial payload capabilities would neither be technologically difficult nor prohibitively expensive."
But even if the endeavor is financially possible, there is no real-world proof that it will work as expected, and the scientists acknowledge they are putting forth a hypothetical.
"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."
Further, the technique involves potential risks:
[C]oordination between multiple countries in both hemispheres would be required, and stratospheric aerosol injection techniques could jeopardize crop yields, lead to droughts or cause extreme weather.