I don't know about methane but they say the CO2 levels were many times higher than they are now when flowering plants first evolved. It doesn't seem logical to me that such a specialized development would first occur when conditions were minimal. Most modern animals, including us, wouldn't exist if it weren't for flowering plants.
Would conditions for us be better if CO2 went back to Triassic era levels? I don't know but we'd better hope nothing causes CO2 to fall below the level that flowering plants can survive.
actually, I meant to type “planet change” but yeah- when the plants die it sure changes the planet
Some theories now that an asteroid impact didn’t cause the atmospheric change that killed the dinosaurs, but that the change was triggered by massive volcanic and/or methane eruptions or releases, perhaps from undersea
We know there is an entire dead frozen trapped continent under the Antarctic ice shelf with mountains, valleys and rivers- the piri reis map and other modern sources