Nuclear power
People claim nuclear power mitigates CO2. What these people do not look at is how much CO2 is emitted in the mining of the ore, transporting of the ore, processing of the ore into yellow cake, transporting the ore and then making the reactor rods, transporting the reactor rods. Then these people do not consider how long the waste material takes to decay in a half cycle. Its something like 500,000 years. A very long time.