Natural gas is central to global energy: worldwide consumption has been rising rapidly and in 2018 it accounted for half of the growth in total global energy demand1. Gas has significantly lower CO2 emissions on combustion per unit of energy than either coal or oil but higher emissions than nuclear and most renewable energy sources2. Studies that looked at the so-called ‘bridging’ role of gas in the transition to a low-carbon energy system indicated good potential for gas to act as a transition fuel to a low-carbon future up to 2035 globally under certain conditions3. A key caveat in this bridging scenario is that its potential varies significantly across regions and between sectors4. One crucial factor affecting the decarbonisation potential of gas is the level of fugitive methane emissions that occur during its production, transportation and distribution5. Furthermore, in the long term, the imperative to eliminate most fossil fuel-related GHG emissions could pose a profound challenge to the gas business, which could end up with high carbon, stranded assets. Questions about the role of gas in a low-carbon energy future remain: Can gas substitute for coal as a ‘bridging fuel’? Is it genuinely useful to lower emissions or rather a convenient way to stimulate the market for gas? This briefing note attempts to explore these questions.