Natural gas has been touted as a “bridge fuel” that can help the United States and the world reduce emissions of global warming pollutants during the transition to truly clean sources of energy. The “bridge fuel” argument, however, hinges on a critical assumption: that the climate impacts of natural gas are modest.
In recent years, a number of studies have challenged that assumption, finding that natural gas production, transportation and storage result in major leaks of methane to the atmosphere that erode or nullify the climate benefits of shifting to natural gas. These findings should lead policymakers to reject natural gas as a “bridge fuel” and instead lead them to redouble America’s efforts to repower with truly clean energy from the sun, the wind and other renewable sources of energy.
Methane is a powerful global warming pollutant.
Multiple studies, summarized in Table ES-1 and in greater detail in this report, find high methane leakage rates from both unconventional sources of natural gas, such as shale gas produced through fracking, and from conventional sources of gas that we’ve tapped for decades.
Table ES-1. Summary of Recent Studies Showing High Methane Emissions from Natural Gas (methane leakage as a percent of natural gas produced)
The table shows the percentage of produced natural gas that is lost to the atmosphere. “U” indicates the methane leakage estimate is for “upstream” emissions from gas production and processing only. Therefore, total emissions—including “downstream” emissions from natural gas storage, transmission and distribution—are higher than listed here.
Several studies that have found a substantial global warming emission benefit from natural gas use compared to other fossil fuels have used questionable assumptions or methodologies.
The rising doubts about the climate benefits of natural gas raise the level of urgency for the United States to implement clean, renewable sources of energy—such as solar and wind power—with unambiguous benefits for the global climate. In addition, the United States should slow efforts to develop gas resources using dangerous technologies such as fracking that have major impacts on public health and the environment.