I think it's important to at least partially separate the issues of climate change from plastic pollution. For some reason these two have become entwined together in the public mind. We need to get a handle on plastic pollution, and yes, it's a product of the petrochemical industry so there is that, but it's not the same type or scale of problem as the emergency around tailpipe / smokestack CO2 or methane emissions.
Does decomposing plastic emit methane?