Mitigating climate threatsAn Umbrella to Combat Warming
Research examines the possibility of spraying tiny particles into the stratosphere to block the sun a bit and cool the planet. Shielding the Earth with a mist of tiny particles sounds like the stuff of sci-fi movies, but since it was first proposed in the 1950s the idea has gained traction among scientists around the world to shield us not from extraterrestrials, as Hollywood might have it, but from the sun. Known as solar geoengineering, the concept is to send planes into the stratosphere — 6 to 31 miles above the Earth — to spray particles that can reflect sunlight back into space and cool the planet.
Every morning, the Keutsch Research Group gathers for a meeting. Eight engineers and chemists give updates on their preceding day’s work: ordering parts, transferring software, untangling an administrative snafu. The whole affair usually lasts less than 15 minutes.
Scheduling vacations and requisitioning supplies do not scream “high stakes,” but the group’s project could someday have major consequences for global climate change. It is controversial, however. Some even fear it could make things worse. Right now the group is waiting for approval to schedule a new experiment in the stratosphere.
Their idea? To shield the Earth with a mist of tiny particles. It sounds like the stuff of sci-fi movies, but since it was first proposed in the 1950s the idea has gained traction among scientists around the world to shield us not from extraterrestrials, as Hollywood might have it, but from the sun. Known as solar geoengineering, the concept is to send planes into the stratosphere — 6 to 31 miles above the Earth — to spray particles that can reflect sunlight back into space and cool the planet.
Working in collaboration with colleagues from the Keith Group — more than a dozen environmental scientists, engineers, economists, and political scientists under the leadership of David Keith, Gordon McKay Professor of Applied Physics at the Harvard John A. Paulson School of Engineering and Applied Sciences (SEAS) and a professor of public policy at the Harvard Kennedy School — the Keutsch Group is hoping to uncover some answers about the possibilities of such a scheme with a project they call the Stratospheric Controlled Perturbation Experiment, or SCoPEx.
The need for a bold new plan seems clear.
Global carbon dioxide (CO2) emissions reached an all-time high in 2018. In October, the United Nations’ Intergovernmental Panel on Climate Change (IPCC) announced that those emissions must drop drastically to limit global warming to acceptable levels. In 2017, according to the IPCC, global warming reached 1 degree Celsius above preindustrial levels. To keep it from going more than half a degree higher, the panel recommends cutting emissions by about 45 percent by 2030 and to “net zero” by 2050. The panel’s website concedes, however, that even these drastic changes would mean that “any remaining emissions would need to be balanced by removing CO2 from the air.”
