This Scientist Has a Risky Plan to Cool Earth - solar geoengineering. There's Growing Interest.

[Bundbuster]

David Keith wants to spray a pollutant into the sky to block some sunlight. He says the benefits would outweigh the danger.

https://www.nytimes.com/2024/08/01/climate/david-keith-solar-geoengineering.html?unlocked_article_code=1.AE4.y4hQ.EHn4G1aJnzi5&smid=url-share

David Keith was a graduate student in 1991 when a volcano erupted in the Philippines, sending a cloud of ash toward the edge of space. Seventeen million tons of sulfur dioxide released from Mount Pinatubo spread across the stratosphere, reflecting some of the sun’s energy away from Earth. The result was a drop in average temperatures in the Northern Hemisphere by roughly one degree Fahrenheit in the year that followed. Today, Dr. Keith cites that event as validation of an idea that has become his life’s work: He believes that by intentionally releasing sulfur dioxide into the stratosphere, it would be possible to lower temperatures worldwide, blunting global warming.

Proponents see it as a relatively cheap and fast way to reduce temperatures well before the world has stopped burning fossil fuels. Harvard University has a solar geoengineering program that has received grants from the Microsoft co-founder Bill Gates, the Alfred P. Sloan Foundation and the William and Flora Hewlett Foundation. It’s being studied by the Environmental Defense Fund along with the World Climate Research Program, an international scientific effort. The European Union last year called for a thorough analysis of the risks of geoengineering and said countries should discuss how to regulate an eventual deployment of the technology. But many scientists and environmentalists fear that it could result in unpredictable calamities.

Because it would be used in the stratosphere and not limited to a particular area, solar geoengineering could affect the whole world, possibly scrambling natural systems, like creating rain in one arid region while drying out the monsoon season elsewhere. Opponents worry it would distract from the urgent work of transitioning away from fossil fuels. They object to intentionally releasing sulfur dioxide, a pollutant that would eventually move from the stratosphere to ground level, where it can irritate the skin, eyes, nose and throat and can cause respiratory problems. And they fear that once begun, a solar geoengineering program would be difficult to stop.

“The whole notion of spraying sulfur compounds to reflect sunlight is arrogant and simplistic,” the Canadian environmentalist David Suzuki said. “There are unintended consequences of powerful technologies like these, and we have no idea what they will be.” Raymond Pierrehumbert, an atmospheric physicist at the University of Oxford, said he considered solar geoengineering a grave threat to human civilization. In a series of interviews, Dr. Keith, a professor in the University of Chicago’s department of geophysical sciences, countered that the risks posed by solar geoengineering are well understood, not as severe as portrayed by critics and dwarfed by the potential benefits.

Much, much more at link - should be no paywall.