Academy of Finland’s FICCA funded COOL Project.
“Another technique examined was the use of commercial passenger aircraft flying at high altitudes to inject sulphate aerosols, emitted by aviation fuel, into the stratosphere. This would mimic a volcanic eruption, during which sulphur compounds are released into the stratosphere. They reflect solar radiation and thereby have a clear cooling effect on the climate. No previous calculations are available on the viability of using commercial flights in this way.
“In terms of efficient geoengineering strategies, this technique proved unviable. It would work best close to the equator, but little air traffic operates there – commercial flight routes are operated further north. In addition, current commercial aircraft are unable to fly high enough in the stratosphere. We would need new planes with large amounts of sulphur added to their fuel,” Laaksonen says.
Commercial aircraft could be used to deliever sulfate into stratosphere by increasing fuel sulfur content and the flight altitude of inter-continental flights • The sulfur content of the fuel should be increased to about 50 times the current level to have a significant cooling effect • The cooling effect would be confined to the Northern Hemisphere