From his glass-walled, 57th-floor apartment overlooking Chicago, David Keith can see the whole of the sky. When I visited him there on a clear day this summer, the pale blue stretched from the surface of Lake Michigan up toward the edge of space.
It is up there in the stratosphere that Keith, a professor in the University of Chicago’s department of geophysical sciences, wants to alter the very composition of the air.
He believes that by releasing many tons of sulfur dioxide roughly 12 miles, or 20 kilometers, above the ground, it would be possible to reflect some of the sun’s energy away from Earth. Doing so would effectively turn down the planet’s thermostat, slowing down global warming.
It’s an audacious gambit that’s fraught with controversy, as I wrote in an article published Tuesday morning.
I had come to Chicago to talk to Keith about this proposed technology, which is known as stratospheric solar geoengineering. While it can seem like the stuff of science fiction, ambitious proposals to alter the planet’s climate are increasingly being taken seriously as the effects of global warming grow more acute.
There are already major efforts underway to suck carbon dioxide out of the air. Experiments to brighten clouds to deflect the sun’s energy are also being carried out.
Keith is a leading intellectual figure in the geoengineering movement.
He has been publishing scientific papers on the topic for more than 30 years. When the Microsoft co-founder Bill Gates wanted to learn about climate technology, he asked Keith to lead a series of meetings for him. Keith then started a company, Carbon Engineering, which developed a process to pull carbon dioxide out of the air. The company was acquired by Occidental Petroleum last year for $1.1 billion, delivering Keith a personal windfall of $72 million.
He has moved from the University of Calgary to Harvard and now to the University of Chicago, which is allowing him to hire 10 new faculty members and start a new $100 million geoengineering program.
Critics of solar geoengineering say even researching it is dangerous. They contend that if deployed, the technology could trigger unintended consequences, such as disrupting India’s monsoon. They argue it gives people the false impression that it will be possible to stop global warming without phasing out fossil fuels. And they worry about what would happen if solar geoengineering were to begin, and then end suddenly, causing worldwide temperatures to spike.
Those are just a handful of the scenarios explored in some of the popular science fiction that has used solar geoengineering as a plot point. In the “Snowpiercer” series, the world is thrust into an ice age after the sun is blocked. In the novel “Termination Shock,” a Texas billionaire starts a rogue effort to seed the stratosphere with sulfur dioxide, setting off a chain reaction of geopolitical showdowns. And in another novel, “Ministry for the Future,” the Indian military starts solar geoengineering after a deadly heat wave hits the country.
In a series of interviews, Keith told me he believes that the risks are not as severe as portrayed by critics, while being dwarfed by the potential benefits. If solar geoengineering slowed the warming of the planet by even just one degree Celsius, or 1.8 degrees Fahrenheit, over the next century, he said, it could help prevent millions of heat-related deaths each decade.
“There certainly are risks, and there certainly are uncertainties,” Keith told me. “But there’s really a lot of evidence that the risks are quantitatively small compared to the benefits, and the uncertainties just aren’t that big.”
Despite the potential risks, interest in solar geoengineering is gaining steam. 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.
Keith tried to perform a solar geoengineering experiment while at Harvard, but those efforts were scuttled by public protests led by Indigenous people. While Harvard has no plans to try another field experiment, Keith hopes his new program in Chicago will continue the work.
It all suggests that, while stratospheric solar geoengineering may not occur at a large scale anytime soon, the idea is moving out of the realm of science fiction and into the mainstream.
“While there are still lots of strong individual voices of opposition, there are a lot of people in serious policy positions that are taking it seriously,” Keith told me. “And that’s really exciting.”
Read the whole article here.
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