During the second flight, in September 2022, the smaller payload balloon burst about 15 miles above Earth while expanding amid decreasing atmospheric pressure, releasing about 400 grams of gas into the stratosphere. That may be the first time that a measured gas payload has been verifiably released into the stratosphere as part of a related geoengineering effort. Both balloons were launched from a launch site in Buckinghamshire, in the south-east of England.
However, there have been other attempts to place sulfur dioxide in the stratosphere. Last April, the co-founder of a company called Make Sunsets says he tried to launch it during a couple of rudimentary balloon flights from Mexico, as MIT Technology Review previously reported late last year. It’s also unclear if it was successful, as the aircraft did not include equipment that could confirm where the balloons burst, said Luke Iseman, CEO of the startup.
The Make Sunsets effort was widely denounced by geoengineering researchers, critics of the field, and the government of Mexico, which has announced plans to ban and even halt any solar geoengineering experiments in the country. Among other issues, observers were concerned that the releases had been made without prior notice or approval, and that the company ultimately seeks to monetize such releases by selling “cooling credits.”
Lockley’s experiment was different in a variety of ways. It was not a commercial company. The balloons were equipped with instruments that could track flight paths and monitor environmental conditions. They also included a number of safety features designed to prevent the balloons from landing while they are still filled with potentially dangerous gases. In addition, the group obtained permits to fly and submitted what is known as a “notice to aviators” to aviation authorities, which ensure that aircraft pilots are aware of flight plans in the area.
Some observers said the amount of sulfur dioxide released during the UK project does not present any real environmental danger. In fact, commercial flights typically produce many times more.
“This is a harmless article or harmless experiment, in the direct sense,” says Gernot Wagner, a climate economist at Columbia University and author of Geoengineering: The gamble.
But some are still concerned that the effort was carried out without broader public disclosures and commitment up front.
Shuchi Talati, a resident scholar at American University who is forming a nonprofit focused on governance and justice issues in solar geoengineering, fears there is a growing disregard in this space for the importance of research governance. That refers to a set of norms and standards related to the scientific merit and oversight of proposed experiments, as well as transparency and public engagement.