Yes, obviously AI is emitting way too much. It shouldn't even be producing 0.2% of global emissions, let alone 2%. My main grievance is that no one ever talks about improving industrial and agricultural processes even though they produce around 29% of emissions and 20% of emissions respectively.
Anaerobic bacteria produce methane. When oxygen is present, the aerobic pathway outcompetes anaerobic because more energy is available, producing CO2 instead.
GHG are usually measured in tonnes of CO2 equivalent (GWP) where methane is about 80x as much warming as the same mass of CO2 over a 20 year period, or about 25x as much warming over a 100 year period.
This is also what's going on in the steady replacement of various refrigerants with lower-GWP alternatives.