I strongly recommend keeping this idea in your back pocket. There are a few ways to accomplish geoengineering to reduce solar gain with technology we have now. It will cost taxpayers a staggering amount of money, will likely punch down on poorer countries anyway through modified weather patterns, crop yields may suffer, air quality may get worse in ways you can't imagine, but it will work for a limited time. Right now it's a game of chicken where we want governments and big business to do anything else first. If we flinch and dim the skies, the petroleum industry will just burn more and faster, throwing away the time we just bought, delaying doomsday by a few decades instead.