[hannob]

Methane emissions from incomplete burning, and also from upstream.

Methane emissions are an issue with basically all uses of gas that has been underestimated in the past and only in recent years it's more widely recognized how problematic that is. A lot of the "gas is greener than X" messaging from the past is simply no longer true if you consider methane emissions.

[VBprogrammer]

Methane emissions from oil extraction aren't negligible either so it depends on your point of reference. It's almost certainly better to burn methane in a power plant and use BEVs where possible but that's a long way from possible in heavy goods vehicles for example (they will need batteries measured in MWh for a start).

There are also many dimensions to emissions, global warming potential is important but from a personal point of view I worry more about the impact on my children's health from the other emissions like particulates, NOx and aromatic hydrocarbons.