The world is facing a climate crisis, there’s no doubt about it. Some of the best and brightest minds in the world are working hard to come up with solutions. One such solution involves “climate engineering” in the form of spraying sulfur dioxide in the upper atmosphere to create a sulfuric acid cloud, as large volcanic eruptions do.
But as with most things, there are potential unintended consequences.
First, sulfuric acid is the main component of acid rain, which devastates forests, acidifies waterways to the detriment of aquatic life, and corrodes building materials and paints. In the United States, there were extensive efforts to clean up emissions from coal-fired power plants and steel refineries after it was discovered in the late 1970s that acid rain from these factories’ emissions was devastating forests in the Northeast.
Secondly, even if the world’s scientists decided that the risk of acid rain was less than the risk of absolute ecological disaster and decided to go ahead with their mission of spraying sulfur dioxide into the upper atmosphere, new research from Rutgers University shows that suddenly stopping the spraying would have a devastating effect on animals and plants.
Basically, if the spraying were to stop, the atmosphere would warm rapidly.
“Rapid warming after stopping geoengineering would be a huge threat to the natural environment and biodiversity,” said study lead author Rutgers Distinguished Professor Alan Robock. “If geoengineering ever stopped abruptly, it would be devastating, so you would have to be sure that it could be stopped gradually, and it is easy to think of scenarios that would prevent that. Imagine large droughts or floods around the world that could be blamed on geoengineering, and demands that it stop. Can we ever risk that?”
But how would “climate engineering” with sulfur dioxide work? Basically, the cloud of sulfuric acid that forms after the airplanes spray sulfur dioxide would reflect solar radiation and cool the planet. The spraying would lead to an even distribution of sulfuric acid clouds in the Northern and Southern Hemispheres, which could lower the global temperature by about 1 degree Celsius—about the level of global warming since the Industrial Revolution began in the mid-1800s.
However, planes would have to fly continuously into the upper atmosphere to maintain the cloud, because it would only last about a year if spraying stopped. But plants and animals simply can’t evolve that quickly, much less move quickly enough to find suitable new habitats.
“In many cases, you’d have to go one direction to find the same temperature but a different direction to find the same precipitation,” Robock said. “Plants, of course, can’t move reasonably at all. Some animals can move and some can’t.”
Another possible complication of the spraying plan: one side effect of it would be an El Niño warming of the surface waters in the Pacific Ocean, which would cause a devastating drought in the Amazon.
Ultimately, what it all comes down to is that sulfur dioxide spraying may not be a viable option to keep global climate change under control. Between the effects of acid rain and the need for animals and plants to find suitable new habitats rapidly if the spraying stops and the temperatures changes rapidly, spraying of sulfur dioxide sounds like it could well cause more problems than it cures.