https://climate.mit.edu/ask-mit/why-do-we-compare-methane-ca... "Over 20 years, the methane would trap about 80 times as much heat as the CO2. Over 100 years, that original ton of methane would trap about 28 times as much heat as the ton of CO2."

So converting a bunch of atmospheric CO2 to methane evey year is not good.