Methane is 28 times as potent a greenhouse gas as CO2 is and it has increased from 0.5 PPB in the preindustrial era to present levels around 12.5 PPB currently.
Atmospheric levels of methane, a powerful greenhouse gas, are spiking, scientists report
By Chris Mooney
...methane, the second most important greenhouse gas. Atmospheric concentrations of this gas — which causes much sharper short-term warming, but whose effects fade far more quickly than carbon dioxide — are spiking, a team of scientists reports in an analysis published Sunday in the journal Environmental Research Letters.
Methane concentrations in the atmosphere, they report, were rising only at about .5 parts per billion per year in the early 2000s. But in the past two years, they’ve spiked by 12.5 parts per billion in 2014 and 9.9 parts per billion in 2015. With carbon dioxide rising more slowly, that means that a higher fraction of the global warming that we see will be the result of methane, at least in the next decade or so.
“Methane in the atmosphere was almost flat from about 2000 through 2006. Beginning 2007, it started upward, but in the last two years, it spiked,” said Rob Jackson, an earth scientist at Stanford University who co-wrote the study.
The paper’s first author was Marielle Saunois, a researcher at the French Laboratoire des Sciences du Climat et de l’Environnement. Saunois and Jackson are part of a larger team of researchers with the Global Carbon Project, which tracks the flows of this element across the planet (carbon is a component of both carbon dioxide and methane), and publishes a global methane budget every two years. The latest budget is here.
“Looking at the scenarios for future emissions, methane is starting to approach the most greenhouse gas-intensive scenarios,” Jackson said. “That’s bad news. We’re going in the wrong direction.”