The central tragedy in aquatic geoengineering is its superfluousness and cost. We already know how to combat climate change. Investing in alternative renewable energies, nuclear power including fusion, sensible environmental regulations and protections, and investments in public transit all work.
These all require sacrifice and political will. Geoengineering is a pie in the sky. It is a pipe dream, a perennial and seductive concept because it allows humanity to solve the problems of decarbonization, and energy transformation, without fundamentally altering the technology, behaviors, or structures which caused the problems in the first place.