Natural gas is 95% methane. Coal is a fraction of a fraction of a percent methane. When coal leaks, it ends up as a bunch of rocks on the side of a rail track. When natural gas infrastructure leaks, it dumps Megatons of methane into the atmosphere. The research and reporting on this topic are clear, natural gas has a significantly higher heating impact than coal, with no doubt.
Natural gas as a “bridge fuel” was just as much a lie as “clean coal”, a PR campaign to support lobbyists in their efforts to prevent regulation.