Methane is far more than 25 times as potent as CO2 as a greenhouse gas. It's all relative to the time that methane exists before oxidizing to CO2. The 25x figure is measured over a century but methane only lasts for about 9 years, during which its greenhouse warming effect is around 140x CO2.

There is much industry pressure to stretch the time window by which methane's greenhouse warming potential is measured, because the longer the period the less harmful methane looks.