Earlier quoted context omitted.
It's not all landfills, it's a small collection of landfills. And if they aren't fixed, even if everybody went zero waste today, those landfills would still be emitting large amounts of methane. Proper landfill design & operation ensures the landfill is aerated, which keeps decomposition primarily aerobic which produces little methane. A poorly designed or operated landfill with little aeration will switch to aerobic…
> even if everybody went zero waste today, those landfills would still be emitting large amounts of methane. If everyone went zero waste then nothing would be added to the landfill, and its methane production would taper out to nothing as a result.
From the top charts for image search "landfill gas chart", suggests methane(CH4) vents heavily for 3-5 years, then a long taper.