Since natural gas emits less carbon than does coal per unit of electricity generation, some analysts suggest natural gas will help to mitigate climate change. However, sociological research has found that the substitution of one natural resource for another often does not happen as anticipated because of political and economic factors. Here, we analyze cross-national time-series data to examine the connection between growth in emissions from natural gas consumption and changes in emissions from coal use, controlling for several structural factors. We find that CO2 emissions from natural gas sources do not displace CO2 emissions from coal. These results cast doubt on whether the growing use of natural gas is likely to help substantially reduce CO2 emissions.