As the world fights to relinquish its burning of fossil fuels, researchers are perusing whether atmospheric geoengineering could assist limit warming and prevent climate catastrophe.
One possible method, solar radiation management (SRM), seeks to reflect the sun’s waves back into space, with the most well-known suggestion being to blast Sulphur dioxide – a coolant – into the higher ranges of the atmosphere.
Arguments about its effectiveness abound, with Europe, the United States and several ecological groups speaking out about the advantages and risks. The debate is mainly theoretical at present, with only a few small-scale ventures in operation.
The idea of inserting Sulphur dioxide (SO2) into the atmosphere is not new. The U.S. National Academy of Sciences anticipated the idea as early as 1992, while researchers have recognized that volcanic eruptions, which emitted huge amounts of SO2 into the air, have a conserving effect on the planet.
Efforts to banish SO2 as a destructive air pollutant in China and elsewhere over the last decade have diminished its cooling effect and “unmasked” heat instigated by greenhouse gases, thus contributive to rising global temperatures.
U.S.-based start-up Make Sunsets, one of the few commercial ventures concerned in the sector, released two weather balloons comprising Sulphur dioxide in Mexico last year, instigating the Mexican government to ban the activity in January.
Company organizer Luke Iseman informed Reuters that it was more “upfront” to initiate projects in the United States and 30 introductions had already taken place, backed by selling “cooling credits” to customers.
But apart from Make Sunsets, only a trivial number of other explore projects have been conducted so far, including the launch of a high-altitude weather balloon in southeast England in 2022 to examine the feasibility of aerosol injection equipment.
Some other developments have been annulled as a consequence of public disagreement, including a Harvard University and Swedish Space Corporation project in 2021.
Research has been conducted into other possibly less hazardous SRM technologies, including marine cloud enhancing, which includes the spraying of salt-water from ships to make clouds more reflective.
While these approaches were less intrusive and less potentially harmful than stratospheric aerosol injection, they could prove more costly and too energy-intensive, Benjamin Sovacool, Professor of Earth and Environment at Boston University indicated. Sovacool studied their potential deployment at the Great Barrier Reef.
Dozens of researchers are calling for “a complete international assessment” into the usage of SRM in order to recognize the risks involved and the guidelines that might be compulsory to deploy the technologies on a broader scale.
They informed in a letter published, that it was doubtful that carbon emissions can be reduced or removed rapidly enough to regulate temperature surges below 2 degrees Celsius and that SRM interferences could be made accessible when needed to avoid climate tipping points.
Rivals of the scheme say that although the injection of sulphate sprays might cool the planet, the side effects could demonstrate even more critical. One group of 60 researchers launched a global initiative last year meant to persuade governments to prohibit outdoor solar geoengineering trials.
The group cautioned that the dangers of SRM were too great and that it could influence weather patterns, agriculture, and “the facility of basic needs of food and water”.
Critics argument point to models that show SRM could disturb monsoons and cause droughts in Africa and Asia. Others inform it could also slow down the recovery of the ozone layer or result to a dangerous increase in acid rain.
The technology could even be weaponized by “rogue states” or dishonest private companies and produce new geopolitical and safety threats, the United Nations Environment Program (UNEP) cautioned in a report published this year.
Rivals also concern that the technology could assist as an excuse to delay the change towards net-zero greenhouse gas emissions. Critically, even if SRM involvements successfully keep temperatures down, they will not fix other significances of increasing CO2 levels, like ocean acidification.
“It is significant that people recognize that SRM technologies … do not resolve the climate calamity because they do not decrease greenhouse gas emissions nor inverse the influences of climate change,” said Andrea Hinwood, the UNEP’s chief researcher.
Its influence will also only be brief, increasing the likelihood that countries would be required to deploy SRM for centuries.
“Once you’ve dedicated to it, you’ve got to keep doing it,” said Laura Wilcox, an environment expert. “If you halt, then you’re going to see all of that warming that you’ve lost, essentially on climate timescales overnight. So, it’s a dangerous game.”
