As President Barack Obama heralds the ratification of the Paris climate agreement, a new study shows that methane emissions from the fossil fuel industry are far higher than previously estimated.

According to the research published online Wednesday in the journal Nature, they may be as much as 60 percent greater.

“Our study shows that leaks from oil and gas activities around the world are responsible for a lot more methane than we thought,” said co-author Lori Bruhwiler, a National Oceanic and Atmospheric Administration (NOAA) research scientist, in a press statement.

Out of the 623 million tons of methane—which comes in second after CO2 for greenhouse gas potency—emitted by all sources annually, fossil fuels are responsible for 132 million to 165 million tons, or roughly 20-25 percent, the team lead by NOAA and the Cooperative Institute for Research in Environmental Sciences (CIRES) scientists found.

Using the emissions’ “isotopic signatures,” the researchers were able to determine if the they were from fossil fuels or other sources.

The study’s abstract states: “Our findings imply a greater potential for the fossil fuel industry to mitigate anthropogenic climate forcing, but we also find that methane emissions from natural gas as a fraction of production have declined from approximately 8 percent to approximately 2 percent over the past three decades.”