And I'm not a scientist, but I think 75 years is not enough. CO2 is not going to disappear by itself, it has a lifespan of 1000 years, so you would need ~13 jumps to get rid of todays CO2. And first jumps will be probably really messy - the climate is so messed up right now that acid rain clouds are (probably) protecting us from warming. If you shut everything down, temperature will goes up, not down. At least initially..