Global emissions of methane, a greenhouse gas multiple times more potent than carbon dioxide, rose by 9 percent in the decade through 2017, putting Earth on a track to warm by more than 3 degrees Celsius by the end of the century, according to an international study scheduled to be released Wednesday.
Atmospheric levels of the gas — emitted by digesting cows, leaky gas pipelines and natural sources such as wetlands — have increased 2½ times from pre-industrial levels, researcher Marielle Saunois said in a press briefing in Paris. Human activity accounts for about 60 percent of methane emissions, led by growing herds of livestock and emissions linked to oil and gas production.
Methane’s warming potential over a century is 28 times that of an equivalent mass of CO2, the researchers said. The current path of methane emissions lies between the two warmest scenarios used in projections by the Intergovernmental Panel on Climate Change, implying large cuts are needed to meet Paris agreement targets. Warming by 3 degrees would be double the rate scientists have identified as needed to constrain the worst impacts of climate change.