Since use of natural gas emits less carbon dioxide (CO2) than other fossil fuels and CO2 is an important greenhouse gas, policies to encourage greater natural gas use are often touted as one strategy to reduce global warming. In this analysis, we examine the impacts of lower natural gas prices, brought about by government initiatives or market forces, on greenhouse gas emissions. The most surprising result of this analysis is that lower gas prices appear to have little impact on US greenhouse gas emission trends. However, lower gas prices and commensurate overall lower fossil energy costs do defer energy conservation efforts, stimulate more energy use economy-wide, and may displace cleaner renewable sources of energy. These results argue for a careful examination of attributes needed to align policy options intended to increase efficient gas use and those intended to lower overall greenhouse gas emissions.