> As a result, bioplastics often end up in landfills where, deprived of oxygen, they may release methane, a greenhouse gas 23 times more potent than carbon dioxide.
...and then decomposes into CO2 anyway. So you get a short-lived (10 years) very potent greenhouse gas, and then the long-term effect of CO2 on top of that. So whichever way you slice it, releasing methane is strictly worse than releasing CO2.
> As a result, bioplastics often end up in landfills where, deprived of oxygen, they may release methane, a greenhouse gas 23 times more potent than carbon dioxide.