Scientists have discovered that the recent spike in global temperatures may be caused by a reduction in sulfur dioxide pollution from shipping vessels. Ships have long emitted sulfur dioxide, which cools the planet by seeding clouds and reflecting sunlight. However, new regulations that limit sulfur in ship fuels took effect in 2020, leading to a loss of this cooling effect equivalent to a large volcanic eruption each year. Models show this reduction in sulfur dioxide pollution can explain the extra warming seen in the North Atlantic. While pollution is bad, the new regulations provide a natural experiment that gives insight into how intentional geoengineering could potentially combat climate change in the future.
A while back there was a round of interest in the possibility of countering global warming by using specialized high-altitude planes to spray calcium carbonate particulates into the upper atmosphere, and it was calculated that global warming could be countered with an ongoing expenditure of $2 billion per year. That’s peanuts for a country like China, so if climate change starts causing them significant identifiable losses I wouldn’t be at all surprised if they gave it a go.
