Question

Question #65884

Answer 1

Photosynthesis.

Explanation:

From a natural "earth science" perspective, that is the only mechanism.

There are other man-made synthetic pathways that may be useful in recycling excess `CO_2` more quickly. They all involve catalytic reactions that "reverse" the combustion process essentially, forming `CH_4` and other hydrocarbons from `CO_2`. Methanol is another useful molecule that can be made relatively easily from `CO_2` and `CH_4`.