In fact, research in the US has found that shale gas wells are often far less leaky than their conventional brethren. Role of atmospheric oxidation in recent methane growth. If methane sinks weaken, atmospheric concentrations of methane may continue to rise even if emissions are constant.
These "top-down" readings add to traditional "bottom-up" readings, or measurements taken right at the potential emission source, often at ground level.
The new studies will help refine the global estimates that do exist while improving national estimates. Methane from biological sources such as cows and wetlands have a low carbon content -- compared to methane from most fossil fuels.
International Energy Agency. However, relatively little is known about emissions from one of its largest man-made sources, the oil and gas industry. It's the low-hanging fruit to slow global warming. Neither the citations provided by Howarth nor the report provide data on the share or levels of coal mined from the surface or underground mines.
CH4 emissions from oil and gas production: Have recent large increases been detected?
So inwe launched an extensive series of 16 independent, rigorously executed projects. Phase 2, which started inconsists of field studies using multiple measurement methods. Accessed: 19th August International Energy Agency.