For years, scientists have warned that aerosols seriously damage the ozone layer, but a new study suggests they could in fact alleviate climate change.
Researchers at Harvard have identified an aerosol that kills two birds with one stone, by repairing ozone damage and cooling the planet in the process.
The approach is known as solar engineering and involves injecting light-reflecting sulfate aerosols into the atmosphere to reduce the sun’s ferocity.
“In solar geoengineering research, introducing sulfuric acid into the atmosphere has been the only idea that had any serious traction until now,” said David Keith, professor of public policy at Harvard and the study’s first author.
“This research is a turning point and an important step in analyzing and reducing certain risks of solar geoengineering.”
Previously, researchers have attempted to find an aerosol that is unreactive, minimising damage to the ozone layer.
But the new study takes a different approach.
“Instead of trying to minimize the reactivity of the aerosol, we wanted a material that is highly reactive but in a way that would avoid ozone destruction,” said Frank Keutsch, professor of chemistry and chemical biology, and a co-author.
The team settled on calcite, one of the most common compounds found in Earth’s crust.
”The amounts that would be used in a solar geoengineering application are small compared to what’s found in surface dust,” Keith added.
But the researchers warned that geoengineering is not a solution to climate change.
“Geoengineering is like taking painkillers,” said Keutsch. “When things are really bad, painkillers can help but they don’t address the cause of a disease and they may cause more harm than good. We really don’t know the effects of geoengineering, but that is why we’re doing this research.”