Scientists suggest spraying chemicals in the atmosphere to slow global warming

NASA photo

(CNN) – Scientists are proposing an ingenious but not yet proven way to combat climate change: the application of chemicals that reduce the emission of sunlight into the Earth's atmosphere.

Research conducted by scientists at Harvard and Yale Universities, published in the journal Environmental Research Letters, proposes to use a technique known as stratospheric aerosol injection (SAI). , which could halve the rate of global warming.

The technique would involve spraying large quantities of sulphate particles in the lower stratosphere at altitudes up to 12 miles. Scientists propose to deliver sulphates with specially designed aircraft, balloons or large naval guns.

Despite the fact that the technology has not yet been developed and no aircraft are suitable for adaptation, the researchers say that "the development of a new tanker specifically designed for the payload would not be technologically difficult, not too expensive. "

They estimate the total cost of launching a hypothetical SAI system in 15 years at around $ 3.5 billion, with operating costs of $ 2.25 billion a year over a 15-year period.

The report recognizes, however, that this technique is purely hypothetical for the moment.

"We are not making any judgment on the desirability of creating an SAI," the report says. "We are simply showing that a hypothetical deployment program starting in 15 years, while being very uncertain and ambitious, would in fact be technically feasible from an engineering point of view. It would also be remarkably cheap.

They also recognize the potential risks – coordination between several countries in both hemispheres would be needed and ISI techniques could jeopardize crop yields, drought or extreme weather conditions.

The proposals also do not address the problem of increasing greenhouse gas emissions, which are one of the main causes of global warming.

And despite the belief of the report's lead authors, some other experts were skeptical.

"From the point of view of the climate economy, the management of solar radiation remains a much worse solution than greenhouse gas emissions: more expensive and much more risky in the long term," Philippe Thalmann of the French company Ecole Polytechnique Fédérale de Lausanne, expert in climate change economics, told CNN.