Both shale gas and conventional natural gas have a larger greenhouse gas footprint than do coal or oil, especially for the primary uses of residential and commercial heating. Dr. Robert Howarth, a professor of ecology and environmental biology, came to this conclusion after assessing the best available data and analyzing greenhouse gas footprints for both methane（甲烷） (including shale gas and conventional gas) and carbon dioxide over a timescale of 20-years following emissions.

The findings are published in Energy Science & Engineering.

"While emissions of carbon dioxide are less from natural gas than from coal and oil, methane emissions are far greater. Methane is such a potent greenhouse gas that these emissions make natural gas a dangerous fuel from the standpoint of global warming over the next several decades," said Dr. Howarth. "Society should wean ourselves from all fossil fuels and not rely on the myth that natural gas is an acceptable bridge fuel to a sustainable future."