Those 100 year timescale numbers are misleading as the impact is so front loaded. They only make sense when talking about an emissions that are constant through long timescales.
I've heard people argue that its both too aggressive and too conservative. I'm in the too conservative camp, we need to figure things out sooner than 100 years and the risk of a feedback loop is high with methane.
Its fine to assert that a single number doesn't capture the nuances of the situation. But we have to keep in mind that
1) the heat trapped by the methane stays trapped even after it has decayed
2) methane concentrations in the atmosphere are increasing significantly faster than co2
3) the more methane in the atmosphere the slower its rate of decay
3) It’s nonlinear, increasing methane concentrations also benefit methane scavenging bacteria which should increase the rate of breakdown as concentrations increase. OH only lasts around 1 second in the atmosphere so in theory it should be depleted by increasing atmospheric methane, but methane is only one of several things it reacts with so the difference is minimal without orders of magnitude change in Methane.
>1) the heat trapped by the methane stays trapped even after it has decayed
Not really. It would be present, but not trapped. Absent other factors, that would mean earth is above its equilibrium temperature and would cool once methane loss permits it to radiate heat more effectively. Either that or it shoots us in the face with a clathrate gun. There's really only one way to find out.
