To elaborate a bit, an atom of carbon in CH4 is around 100x as bad as an atom of carbon in CO2; CH4 is primarily and quickly removed by breaking down into CO2. But the number of carbon atoms we release into the atmosphere as CH4 is much, much less than the number of carbon atoms we release into the atmosphere of CO2. We only care about CH4 because it's 100x as powerful a greenhouse gas as CO2. If we released the methane carbon directly as CO2 carbon, it'd be a measurable amount but dwarfed by other sources.
CO2 concentration: 400_000 ppb
To elaborate a bit, an atom of carbon in CH4 is around 100x as bad as an atom of carbon in CO2; CH4 is primarily and quickly removed by breaking down into CO2. But the number of carbon atoms we release into the atmosphere as CH4 is much, much less than the number of carbon atoms we release into the atmosphere of CO2. We only care about CH4 because it's 100x as powerful a greenhouse gas as CO2. If we released the methane carbon directly as CO2 carbon, it'd be a measurable amount but dwarfed by other sources.