Methane emissions from oil, gas, and coal installations around the world are 20 to 60% higher than many official estimates, including the ones published by the Intergovernmental Panel on Climate Change (IPCC), according to a paper last week in the journal Nature.
The findings have serious implications for efforts to limit average global warming to 1.5° or even 2.0°C, since methane is a shorter-lived but far more potent greenhouse gas than carbon dioxide.
The two-year study, conducted by the U.S. National Oceanic and Atmospheric Administration (NOAA) and the University of Colorado’s Cooperative Institute for Research in Environmental Sciences, was “one of the most exhaustive analyses of long-term global methane emissions and methane carbon isotope records, with implications for climate policy worldwide,” InsideClimate News reports. The study also attributed a massive, ongoing methane spike, first reported by NOAA in 2007, to biological sources like cow flatulence and rotting biomass in landfills.
“It was a substantial effort, with a thorough analysis of uncertainties, to show that the fraction of atmospheric methane emitted from fossil sources (both anthropogenic and natural seeps) is greater than previously thought,” said NOAA methane specialist and study co-author Ed Dlugokencky.
Research by the Environmental Defense Fund had already established that methane leaks from U.S. fossil projects were higher than U.S. Environmental Protection Agency estimates. The new research shows “that we have also been consistently underestimating oil and gas methane emissions on a global scale,” wrote EDF scientist Steven Hamburg.
The study determined that “methane escaping from natural gas, oil and coal production accounts for 132 to 165 million tons of the 623 million tons emitted by all sources every year,” ICN reports. “That makes fossil fuel industries responsible for between 20 and 25% of the global methane problem.”