Cows, rice paddies boosting methane

FRANCE: Global methane emissions from agriculture and other sources have surged in recent years, threatening efforts to slow climate change, an international study has found.

Researchers led by French Laboratoire des Sciences du Climat et de l’Environnement (LSCE) reported that methane concentrations in the air began to surge about 2007 and grew precipitously in 2014 and 2015.

In that two-year period, methane concentrations shot up by 10 or more parts per billion (ppb) annually, compared with an average annual increase of only 0.5 ppb during the early 2000s, according to the study released by the Global Carbon Project, which groups climate researchers.

Marielle Saunois, lead author of the study, said the increase in methane emissions could threaten efforts to limit global warming.

‘‘If we want to stay below a 2 degrees [Celsius] temperature increase, we should not follow this track and need to make a rapid turnaround.’’

Methane is much less prevalent in the atmosphere than carbon dioxide (CO2) – the main manmade greenhouse gas – but is more potent because it traps 28 times more heat. The report did not say to what extent methane contributes to global warming.

CO2 emissions are expected to remain flat for the third year in a row in 2016, thanks to falls in China, the Global Carbon Project said last month.

Saunois said that while the reasons behind the methane surge were not well understood, the most likely sources were cattle farming and rice farming.

Cows expel large quantities of methane and the flooded soils of rice paddies are homes for microbes that produce the gas.

– Reuters