Methane emissions from old oil and gas wells are generally low compared to other sources of the gas, which include livestock burping and flatulent livestock.
That’s according to a new report from Durham University, Newcastle University and the Environment Agency, which investigated more than 100 onshore wells across southern England, the east midlands, Lincolnshire, Yorkshire and Teesside.
Methane concentrations in the soil above each well were analysed, with other measurements taken in the surrounding area to see how these readings compared to background levels of the greenhouse gas.
The greenhouse gas occurs naturally from a range of biological processes in soils, wetlands and the guts of animals as microorganisms break down other carbon-containing molecules.
There are also other potential sources of methane such as coal mines and landfills.
The results showed that while 30% of the well sites had methane concentrations significantly greater than the surrounding environment, 39% had much lower concentrations.
The well emissions that were detected generally occurred within a decade of well closure.