In late March of 2017, at a small summit in Washington, DC, two Harvard professors, David Keith and Frank Keutsch, laid out plans to conduct what would have been the first solar geoengineering experiment in the stratosphere.
Instead, it became the focal point of a fierce public debate over whether it’s okay to research such a controversial topic at all.
The basic concept behind solar geoengineering is that by spraying certain particles high above the planet, humans could reflect some amount of sunlight back into space as a means of counteracting climate change.
The Harvard researchers hoped to launch a high-altitude balloon, tethered to a gondola equipped with propellers and sensors, from a site in Tucson, Arizona, as early as the following year. After initial equipment tests, the plan was to use the aircraft to spray a few kilograms of material about 20 kilometers (12.4 miles) above Earth and then fly back through the plume to measure how reflective the particles were, how readily they dispersed, and other variables.
But the initial launch didn’t happen the following year, nor the next, the next, or the next—not in Tucson, nor at a subsequently announced site in Sweden. Complications with balloon vendors, the onset of the covid pandemic, and challenges in finalizing decisions between the team, its advisory committee, and other parties at Harvard kept delaying the project—and then fervent critiques from environmental groups, a Northern European Indigenous organization, and other opponents finally scuttled the team’s plans.
Critics, including some climate scientists, have argued that an intervention that could tweak the entire planet’s climate system is too dangerous to study in the real world, because it’s too dangerous to ever use. They fear that deploying such a powerful tool would inevitably cause unpredictable and dangerous side effects, and that the world’s countries could never work together to use it in a safe, equitable, and responsible way.
These opponents believe that even discussing and researching the possibility of such climate interventions eases pressures to rapidly cut greenhouse-gas emissions and increases the likelihood that a rogue actor or solitary nation will one day begin spraying materials into the stratosphere without any broader consensus. Unilateral use of the tool, with its potentially calamitous consequences for some regions, could set nations on a collision course toward violent conflicts.
Indeed, there are numerous indicators of growing interest in researching this field and providing funding for it. As noted, the US government is developing a research program. The Environmental Defense Fund is considering supporting scientists in the area and recently held a meeting to discuss guardrails that should govern such work. And a number of major philanthropies that haven’t supported the field in the past are in advanced discussions to provide funding to research groups, sources tell MIT Technology Review.
Meanwhile, under Keith, the University of Chicago is working to hire 10 faculty researchers in this area.
He says he wouldn’t look to lead an outdoor experiment himself at this point, but he does hope that people working with him at the Climate Systems Engineering Initiative would, if it could offer insights into the scientific questions they’re exploring.
“I absolutely want to see experiments happen from the University of Chicago,” he says.