Sorry, but this is utterly false. CO2 is a very low energy state for carbon, and "hydrogenating" carbon (CO2 -> HCOOH/formic acid -> CH2O/formaldehyde -> CH2OH/methanol -> CH4/methane) climbs a ladder towards higher energy states. The life that does this (green plants) use the incoming energy from the sun (outside the system) to do it in a stable fashion and capture the energy into biologically useful (e.g. low-entropy) molecules.
Setting fire to these things is a fast way to increase entropy (locally on this planet, anyway; not sure it would make any material difference on a galactic scale). Fire is a short circuit of electrons flowing from the source (e.g. methane) to the sink (oxygen in the atmosphere). Life is effectively a resistor
in the middle of that circuit that can use the energy slowly and to do "useful work" first, before it is released as heat.
So, the exact opposite of what you wrote.