If possible, would you use artificial means to lower earth's temperature as a preemtive measure against AGW?

Such as genetically engineered algae, industrial CO2 scrubbers, seeding the astmophser with heat-reflecting sulfer particles, detonating nuclear warheads to create a mild nuclear winder effect, exploding an asteroid in earth orbit to filter the sun's radiation, killing every non-essential CO2-expelling mammal, or something else? Any other ways to create an artificial ice age I haven't thought of?