An international research team led by the Laboratoire des Sciences du Climat et de l’Environnement (CNRS / CEA / UVSQ), in cooperation with the firm Kayrros, have achieved a world first by completing a global tally of the largest emissions of methane into the atmosphere by the fossil-fuel industry.

These may be accidental or the result of intentional venting associated with maintenance operations, which account for very large releases.

To obtain their data, the researchers methodically analysed thousands of daily images generated by the ESA’s Sentinel-5P satellite over a two-year period. This allowed them to map 1,800 methane plumes around the globe, of which 1,200 were attributed to fossil-fuel extraction.

They deem the impact of such releases on the climate comparable to that of 20 million vehicles on the road for one year.

These emissions account for 10% of the total estimate for the industry.

The satellite is only able to routinely detect the biggest plumes (>25 tonnes per hour of CH₄), which are also the most intermittent.

The researchers demonstrate that these massive releases of methane are not randomly located but always appear over particular oil and gas extraction sites. As borne out by observations of these releases, whose volumes depend on maintenance protocols and diligence in the repair of leaks, the rules implemented by states and businesses play a major role.

The study: Global assessment of oil and gas methane ultra-emitters, is published in the Journal Science