Ok -- first, let me quote the article:
"Three-hundred and twenty nozzles spewed a cloud of nano-sized droplets engineered to brighten clouds and block sunlight — providing a bit of cooling shade for the coral colonies below."
How big is the Great Barrier Reef?
"approximately 133,000 square miles"
How big is Germany?
"137987.506 square miles"
In other words -- use "cloud brightening" for an area the size of Germany? I would wonder if this is actually a good idea.
How bad is the coral doing? Let's get input from the Australian government":
https://www.aims.gov.au/news-and-media/reef-recovery-window-...
Moderate to High -- without cloud brightening.
Actually, I don't oppose the research. Just be careful if deployments are going to be "at scale".