It's going to cost significantly more energy than the aggregate energy output of all fossil fuel burning over the past 200 years to remove the carbon from the a

It's going to cost significantly more energy than the aggregate energy output of all fossil fuel burning over the past 200 years to remove the carbon from the atmosphere that was added. Probably several multiples more because it's harder to undo chemical combustion than to do it. We're probably talking trillions of dollars, not billions. Much more likely is that we'd invest a few billion in pumping global coolants into the atmosphere, which could be simpler.