Earth's atmosphere is 78% nitrogen, 21% oxygen, 0.9% argon, and 0.03% carbon dioxide with very small percentages of other elements. Humans produce ~3% of that 0.03% which can also be represented as 0. If you double zero you still have zero. Carbon is the gas of life and we couldn't exist without it. If CO2 levels go to low most plant life will die, that's why you don't see trees past a certain elevations on mountains.
Earth's atmosphere is 78% nitrogen, 21% oxygen, 0.9% argon, and 0.03% carbon dioxide with very small percentages of other elements. Humans produce ~3% of that 0.03% which can also be represented as 0. If you double zero you still have zero. Carbon is the gas of life and we couldn't exist without it. If CO2 levels go to low most plant life will die, that's why you don't see trees past a certain elevations on mountains.