New evidence that satellites can accurately monitor greenhouse gas emissions

Global efforts to reduce gas flaring, which contributes to greenhouse gases are five years behind schedule, according to authors of a report published in Nature Sustainability.

The article supports other research which shows satellites are increasingly accurate in monitoring emissions, like methane from coal mines and GHGs from offshore gas wells, and they have proposed that the “Copernicus Sentinel 2” satellite can pinpoint global offshore gas flares to support “scientifically sound decision-making and more targeted regulations”.

The report describes gas flaring (GF) as: “…the controlled burning of excess combustible gases (predominantly methane) that cannot be handled for sale or used for safety, operational or economic reasons.”

The World Bank’s Global Gas Flaring Reduction Partnership (GGFR) says last year gas flaring released an estimated 357 million tonnes of carbon dioxide equivalents (CO₂e), of which 42 mt was methane.

The GGFR has launched an initiative to reach zero routine flaring (ZRF) by 2030.

There is much debate over the use of satellites to measure and detect GHGs, particularly methane.

The Albanese government told Cosmos in August 2022: “…satellite data is not currently reliable enough on its own for emissions estimates, given technical challenges like visibility through clouds or estimates on uneven ground.”

But the report’s authors, led by Professor Yongxue Liu from The School of Geography and Ocean Science at Nanjing University in China, say the Sentinel-2A/2B Multispectral Instrument (MSI): “…can monitor global offshore GF with completeness, spatial explicitness and precision.”

“Although not designed for GHG monitoring, the Sentinel-2A/2B Multispectral Instrument (MSI) may have considerable potential for locating exact GFs and monitoring global GF dynamics because of its high-temperature-sensitive shortwave infrared (SWIR) bands with 20m resolution.”

The European Space Agency says the “Copernicus SENTINEL-2 mission comprises two polar-orbiting satellites aimed at monitoring variability in land surface conditions and surface changes.”

The authors of the Nature report favour MSI to track emissions because monitoring GF in most oil- and gas-producing areas is challenging: “…due to the high expenditure or the inconvenience of field investigations, and consequently, the understandings of the GF distribution, emissions and dynamics are inconsistent, incomplete or even absent.

“Knowledge gaps are particularly acute for offshore GHGs, which are even more difficult to measure, report and validate than onshore GHGs due to inaccessibility.

“Satellites can provide independent worldwide GF monitoring over time and are, therefore, the only objective way of verifying the progress on the GGFR reduction goals.”

Existing monitoring has problems: “GFs that are not sufficiently prominent can be missed, and GFs in close proximity could be confused, leading to uncertainties in subsequent volume estimates and hindering the implementation of targeted regulations.

“Although not designed for GHG monitoring, the MSI may have considerable potential for locating exact GFs and monitoring global GF dynamics because of its high-temperature-sensitive shortwave infrared (SWIR) bands with 20m resolution and a five-day joint revisit cycle at the equator.”