Releasing reflective aerosols into the stratosphere or using any other technique to reflect sunlight away from the earth may not halt sea level rise, according to a new study published in Nature Geoscience. Sea level rise is the biggest concern of climate scientists since 10% of the world's population lives less than 30 feet above sea level. Sea levels are expected to rise by 2.2 feet at the end of the century according to a recent NASA study published in the Proceedings of the National Academy of Sciences Feb 12, 2018.
Details concerning the science can be found at the carbonbrief.org website. Reflecting sunlight away from the earth causes decreasing evaporation and that decreases rainfall in certain regions more than others, especially the North Atlantic region. That increases the salinity of that region, making the water denser and it sinks faster. This speeds up the Atlantic Meridional Overturning Circulation (AMOC). The AMOC transfers heat from the equator to the North Atlantic and faster AMOC will cause more warm water to be buried deep into the ocean. Marine ecosystems would not be protected with this approach.
This is a very important study if it is correct because reflecting sunlight away from the earth was the most likely and discussed technique for
geoengineering the climate in order to prevent a catastrophe. There are no good geoengineering ideas that I know of.