how much energy is spent pulling CO2 out of the air? I know this sounds like a step backward, but perhaps burning plant matter or recycled cardboard might be a

how much energy is spent pulling CO2 out of the air? I know this sounds like a step backward, but perhaps burning plant matter or recycled cardboard might be a more efficient source of CO2? If purifying smoke is cheaper (energy-wise), maybe you could let mother nature extract the CO2 through fast-growing plants, then dry and burn them?