The surge in methane emissions is making the battle against climate change even more difficult, international experts warned.

Global concentrations of methane, a powerful greenhouse gas and one of the causes of climate change, are now growing faster in the atmosphere than any other time in the past 20 years.

According to researchers led by French Laboratoire des Sciences du Climat et de l'Environnement (LSCE), methane concentrations in the air began to rise in 2007 and grew precipitously in 2014 and 2015. Between 2014 and 2015, concentrations climbed up by 10 or more parts per billion (ppb) annually, which is a stark contrast from the early 2000s when methane concentrations increased by just 0.5 ppb on average each year.

Marielle Saunois, lead author of the study and assistant professor at Universite de Versailles Saint Quentin, said that the surge in methane emissions could threaten efforts to limit climate change.

"We should do more about methane emissions. 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," Saunois said in a report by Reuters.

Methane is much less prevalent in the atmosphere than carbon dioxide, but it is a more potent greenhouse gas, trapping 28 times more heat. The growth of carbon dioxide emissions may have flattened out in recent years, but methane emissions seem to be on the rise.

The researchers came up with the 2016 Global Methane Budget, which provided a comprehensive look at how methane had flowed in and out of the atmosphere from 2000 to 2012 because of human activities and other sources.

According to the study, emissions came from natural sources like marshes and wetlands. But about 60 percent of methane added to the atmosphere annually comes from human activities, specifically farming sources, like cattle operations and rice paddies. Cows expel large quantities of methane and the flooded soils of rice paddies are homes for microbes that produce gas. About a third of the human budget comes from fossil fuel exploration, where methane leaks from oil and gas wells during drilling, the researchers said in a press release.

"When it comes to methane, there has been a lot of focus on the fossil fuel industry, but we need to look just as hard if not harder at agriculture," Robert Jackson, a co-author of the paper and a professor in Earth System Science at Stanford University, said in a statement. "The situation certainly isn't hopeless. It's a real opportunity."