The significant atmospheric carbon is in the form of CO₂ and CH₄, which are both greenhouse gases. If we "just" removed the carbon, we'd be left with O₂ and H₂

The significant atmospheric carbon is in the form of CO₂ and CH₄, which are both greenhouse gases. If we "just" removed the carbon, we'd be left with O₂ and H₂, which are mostly harmless.