This paper presents a simple model to describe the impact on global warming of methane (natural gas) when used for energy production. The model is used to estimate the near-term effect of energy policies based on natural gas as a bridge fuel. The results make it clear that the commonly employed global warming potential of methane with a 100-year time horizon has the following problems: <br><br> 1: it produces misleading results;<br><br> 2: is inconsistent with meaningful tracking of greenhouse gas emissions; and <br><br> 3: is incompatible with the precautionary principle.