Robert Howarth, greenhouse gas expert and ecology and environmental biology professor, said they have to control methane immediately, and natural gas is the largest methane pollution source in the US.
He said that if Earth hits a climate-system tipping point because of methane, then our carbon dioxide problem is immaterial, asserting that we have to get a handle on methane, or increasingly risk global catastrophe.
Howarth points to "radiative forcing," a measure of trapped heat in Earth's atmosphere from man-made greenhouse gases. The current role of methane looms large, he says, contributing over 40 percent of current radiative forcing from all greenhouse gases, based on the latest science from the Intergovernmental Panel on Climate Change.
The role of methane as a driver of global warming is even more critical than this 40 percent value might indicate, Howarth notes. The climate system responds much more quickly to reducing methane than to carbon dioxide. If society aggressively controlled carbon dioxide emissions, but ignored methane emissions, the planet would warm to the dangerous 1.5 to 2.0 degree Celsius threshold within 15 to 35 years. By reducing methane emissions, society buys some critical decades of lower temperatures.
The study has been published in the journal Energy Science and Engineering.