Global emissions of methane, a greenhouse gas multiple times more potent than CO2, rose by 9% 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 2 1/2 times from pre-industrial levels, researcher Marielle Saunois said in a press briefing in Paris. Human activity accounts for about 60% of methane emissions, led by growing herds of livestock and emissions linked to oil and gas production.
“We’re on track for a scenario that is rather hot, and above 3 to 4 degrees,” Saunois said in her presentation of the study. “Emissions are rising, particularly in tropical zones.”
After stabilizing in the late 1990s and early 2000s, methane emissions have been rising since 2007, accelerating since 2014, according to the study. Average annual emissions of methane rose to an estimated 596 million tons in the period through 2017, from 546 million tons in the 2000-2006 period.
23% of Warming
The study, the work of more than 90 researchers as part of the Global Carbon Project, was published in the journal Earth Systems Science Data. A related paper on methane sources published in Environmental Research Letters found agriculture and fossil fuels were the main drivers behind increased emissions.