Dutch institutes use methane satellites to find climate impact landfills from hundreds of thousands of cars

Methane is an almost thirty times more potent greenhouse gas than CO₂. SRON researchers are therefore looking for large methane leaks all over the world. A landfill in Buenos Aires appears to emit tens of tons of methane per hour, comparable to the climate impact of one and a half million cars. They also point to landfills in India and Pakistan as major emitters that are finding new low-hanging fruit in the fight against climate change. Published August 10 in Science Advances.

After CO₂, methane is the largest contributor to the anthropogenic greenhouse effect. This is due to its high global warming potential (GWP-100): by weight, methane is almost thirty times stronger as a greenhouse gas than CO₂. So if methane is released during human activity – oil installations, coal mines, livestock barns or landfills – you make it less harmful by burning it and turning it into CO₂. And if you catch it, you can even put that conversion to good use in your central heating boiler or gas stove. SRON researchers have now used satellite data to find a number of waste sites that are low-hanging fruit in the fight against climate change. Four landfills in Argentina, India and Pakistan emit several or even tens of tons of methane per hour.

The SRON methane research team used the Dutch space instrument Tropomi to identify cities with high emissions. Buenos Aires, Delhi, Lahore and Mumbai stood out, with their urban emissions also averaging twice as high as estimates based on global inventories. They then asked the Canadian satellite GHGSat to zoom in, showing that the landfills in these cities are responsible for a large portion of the emissions. The landfill in Buenos Aires emits 28 tons of methane per hour, which can be compared to the climate impact of 1.5 million cars*. The other three landfills are good for three, six and ten tons of methane per hour, which is still equivalent to the impact of one hundred and thirty thousand to five hundred thousand cars.

‘Methane is odorless and colourless, so it is difficult to see where it is leaking,’ says lead author Bram Maasakkers (SRON). “But satellites are ideal for this. With Tropomi, we detect super-emitters that pump large clouds of methane into the atmosphere. It’s an eternal shame because you can fix it with relatively little effort. For example, you can separate and compost the organic waste, so that much less methane is released. And if you mix all the waste anyway, you can still collect or burn the methane gas produced. In addition, methane only has a lifetime of about ten years in the atmosphere, so if we do something about the emission now, we will quickly see the result in the form of less global warming. Of course, it is not enough to limit methane alone, we must also limit CO₂, but we can use it to slow down climate change.’

*Based on US Environment Protection Agency (EPA) estimate of 4.6 tons of CO2 emitted annually by a typical passenger vehicle.

Tropomic

Tropomi is a collaboration between SRON, Airbus Nederland, KNMI and TNO, on behalf of NSO and ESA. Airbus DS NL was the main contractor for the design and construction of the instrument. TNO was responsible for the optical design. The scientific management is in the hands of KNMI and SRON. Tropomi is funded by the Ministry of EZK, the Ministry of Education, Culture and Science and the Ministry of Infrastructure and Water Management.

Photo: Left: Methane concentrations in 2018-2019 measured by Tropomi around Buenos Aires. Right: Zoom in by GHGsat on April 19, 2021, showing methane plumes from the city center landfill. The white arrow indicates the wind direction. Credit: SRON/GHGSat, contains Copernicus Sentinel data (2018-2019), processed by SRON

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