The maths may be right but the thought is wrong since it takes zero trees to offset the whole world's population of air-breathing organisms as all the CO₂ they

The maths may be right but the thought is wrong since it takes zero trees to offset the whole world's population of air-breathing organisms as all the CO₂ they produce started out as... CO₂. This is taken up by algae and plants, which are eaten by organisms which are eaten themselves until the target organism is reached, which will use the energy gained from consuming the previous hop in the carbon chain, breathing out CO₂ upon which the circle is complete. Had humans consumed fossilised carbon the thought would still be wrong since trees only store the carbon temporarily, eventually it is released as CO₂ when the tree burns up or rots away. This leaves aside the whole discussion on whether there is any need to offset CO₂ from non-fossil sources - which there is not as far as I can see.