If plants get most of their mass from CO2 in the air, why is the biomass of plants higher than the amount of CO2 in the atmosphere?

Question

I was reading today that there’s something like 8 gigatons of CO2 in the air, but more than 400 gigatons of biomass on earth (which is mostly plants). Can someone explain how this happens to me?

Edit: My numbers were off. There’s about 10x as much CO2 mass in the atmosphere as there is biomass on Earth

In: 43

Answer 1

You’re approaching the problem backwards. It’s precisely because the plants, and all life in general, are holding the carbon, C, from that CO2 that there is so little of it in the atmosphere. Life is the reason why Earth has so much O2 and so little CO2 in contrast with other planets since O2 is incredibly reactive.