Peter J. Irvine's group has been doing substantial research into what they are calling 'solar geoengineering' or releasing sulfate aerosols into the stratosphere to reduce global temperatures. His research has caught a lot of attention in the media recently.

https://www.tandfonline.com/doi/abs/10.1080/17449626.2018.15...

https://www.nature.com/articles/s41558-019-0398-8