Space research costs peanuts compared to a lot of stuff we do on earth. If we didn't do space research, there's zero chance, the money saved would be spent on worthy causes. So can we stop the "we should use the money for... instead of doing space stuff"? It's just dumb.
The problem isn't research; it's that actually building the thing is a multi-trillion dollar expense, unlikely to succeed, and even if it did succeed, it would have major problems:
It does nothing about ocean acidification, so everything in the ocean with hard body parts dies
You need to maintain it for several hundred thousand years. Humans don't have a track record of doing that for things on earth, let alone in space
It leaves us with a reduced pole-to-equator temperature gradient, resulting in significant changes to weather and rainfall patterns
Would it stop the ocean acidification and fact that we’re headed directly towards a great dying style extinction event where the ocean deoxygenates after oversaturation of co2? Yes, the heat is the immediate concern but the ocean is on the list.
