Yeah, Nuh.
"detonating thermonuclear weapons to throw enough dust above the troposphere to cool the planet down" isn't a real solution, and we've done this before .. leaving aside the two atomic detonations at the end of WWII and looking just at the 2,000 test detonations since (many larger, much larger, than the H & N explosions) the absolute worst case examples were ground level blasts that lifted material into the sky. [1]
[1] https://en.wikipedia.org/wiki/Castle_Bravo
Better fixes include inflating bubbles between the earth and sun to reduce incoming light .. at least that one is reversable and fine tuneable.
Or, you know, maybe consuming less and winding down a bit on the baby making?
