https://www.scientificamerican.com/article/methane-emissions-from-oil-and-gas-may-be-significantly-underestimated/

The fossil fuel industry may be responsible for a much greater share of the world’s methane emissions than previously estimated, according to new research that could intensify urgency around curbing the potent gas from oil and gas production.

The research, published yesterday in the journal Nature, delves into the sources of "fossil" methane emissions, or methane that comes from the Earth’s geologic formations. There are two main ways fossil methane can be released into the atmosphere—human activities from fossil fuel production or natural processes, including the slow release of gas from mud volcanoes or undersea methane seeps.