A professor in the geophysical sciences department at the University of Chicago "believes that by deliberately releasing sulfur dioxide into the stratosphere, it would be possible to lower global temperatures," he says the New York Times.
He is not the only one promoting the idea. “Harvard University has a solar geoengineering program that has received grants from Microsoft co-founder Bill Gates, the Alfred P. Sloan Foundation, and the William and Flora Hewlett Foundation. It is being reviewed by the Environmental Defense Fund along with the World Climate Research Program. But many scientists and environmentalists fear that it could lead to unforeseen disasters."
Because the stratosphere would be used and not confined to a specific region, solar geoengineering could affect the entire world, possibly disrupting natural systems such as rain generation and bringing drought in the monsoon season.
Opponents of the idea worry it would distract from the urgent task of transitioning from fossil fuels to greener ways of creating energy. They oppose the intentional release of sulfur dioxide, a pollutant that can move from the stratosphere to ground level and irritate the skin, eyes, nose and throat or cause respiratory problems. And they fear that once started, a solar geoengineering program will be very hard to stop…
Keith, a professor in the University of Chicago's geophysical sciences department, countered that the risks posed by solar geoengineering are well understood, and not as severe as critics portray. He also argues that they don't think about the potential benefits. If the technique slows global warming by even 1 degree Celsius over the next century, Keith reports, it could help prevent millions of heat deaths every decade…
Opponents of solar geoengineering cite several main risks.
They say it could create a "moral hazard", giving people the wrong impression that it is not necessary to quickly reduce fossil fuel emissions.
The second major concern has to do with unintended consequences.
"It's a really dangerous path to follow," said Beatrice Rindevall, the president of the Swedish Society for Nature Conservation, which opposed the experiment.
"It could shock the climate system, it could change hydrologic cycles, and it could exacerbate extreme weather events and climate instability."
And once solar geoengineering begins to cool the planet, abruptly stopping the effort could lead to a sudden rise in temperatures, a phenomenon known as a "termination shock." The planet could experience "potentially massive warming in an unprepared world within five to 10 years, hitting Earth's climate with something probably not seen since the shock wave that killed the dinosaurs," Pierrehumbert said.
In addition to all this, there are fears of miscreants thinking of using solar geoengineering as a weapon. Not to mention the fact that sulfur dioxide can harm human health.
But Keith is adamant that all these fears are overblown. And while there will be some additional air pollution, he claims the risk is negligible compared to the benefits.
