A new study shows that global emissions of methane from oil and gas production and natural sources combined are 60 to 110 percent higher than the current estimates.

The study, published in the journal Nature, also revealed that methane leak during the production and use of natural oil, gas and coal is 20 to 60 percent higher than estimated. However, the researchers noted that the oil and gas industry is not to blame for the rise of methane concentrations in the atmosphere.

"Methane emissions from fossil fuel development have been dramatically underestimated," said Stefan Schwietzke, a scientist at the US National Oceanic and Atmospheric Administration and lead author of the study, in a statement. "But they're not responsible for the increase in total methane emissions observed since 2007."

For the study, the researchers developed a methodology that avoids debatable assumptions underlying earlier models. The researchers also based their study on a database that's 100 times larger than previous ones.

Their findings revealed that the global methane concentration in the atmosphere have doubled since the 18th century and have mysteriously peaked in 1999. The concentration of methane remained constant until 2007 but started to increase once again. Scientists are not really sure what caused the sudden rise of methane concentration in the atmosphere, but they noted that oil and gas industry is not to blame.

The researchers found no concrete evidence linking the natural oil and gas industry and increased of methane concentrations in the atmosphere. As a matter of fact, methane emissions from these industries have remained constant since 2007 despite the booming natural gas production.

Methane is considered to be the most potent greenhouse gas and is second largest contributor to global warming next to carbon dioxide. While having a relatively shorter life compared to carbon dioxide, methane is 28 times more efficient at trapping the heat on Earth's atmosphere.