Since photosynthesis evolved in the Cretaceous, the global level of CO2 has been capped by photosynthesis on the LAND AND SEAS. The mass extinction at the end of the Cretaceous was caused as CO2 fell below 1 part per million – half the level we have today. 90% of life on Earth died – the biggest mass extinction of prehistory.
The animals evolved to breathe in the O2 excreted by plants: that's right – you breateh in plant waste.
You eat plant bulk, and breathe out CO2.
1 mCO2+(n+r)H2O+UV->(Cm(H2O)n-E)+r(He+O+E2+X-ray) 2O->O2
So both sides of the CARBON CYCLE do Molecular Nuclear Fusion. Otherwise making and oxidising carbon(compounds) would take in heat.
No physicist has commented on biology doing nuclear fusion, down to 0oC. No 10millionoC. This means CO2 is at a pre-industrial 2ppm. A static trace gas affects nothing. Global Warming and man-made Climate Change were paid fiction for nuclear power.
So carbon capped at 2ppm. RSVP.