Scientists constantly warn about the catastrophic effect of carbon dioxide (CO2) on global warming.
But another huge concern is methane, which is more than 28 times as potent as CO2 at trapping heat in the atmosphere.
The primary component of natural gas, methane is responsible for approximately a third of the warming we are experiencing today.
Now, a map has revealed the world’s top 10 methane emitting hotspots where emissions of the potent gas are spiralling out of control.
They include South Sudan’s natural Sudd wetlands, the Kuznetsk Basin in Russia and three coal fields in China.
Combined, these 10 sites emit a total of 28.8 million tonnes of methane per year, according to experts at the University of Bremen in Germany.
[Methane’s] rising concentration in the atmosphere contributes significantly to global warming,’ they warn in a new study.
‘Almost half of the global methane emissions originate from anthropogenic sources, which are dominated by fossil fuel exploitation, livestock, rice cultivation and landfills, whereas the natural emissions mainly originate from wetlands.’
A new map identifies the world’s top 10 methane emitting hotspots where emissions of the potent gas are spiralling out of control, with South Sudan’s natural Sudd wetlands at the top
South Sudan’s natural Sudd wetlands has methane emissions of 4.5 million tonnes per year. Natural emissions of the gas mainly originate from wetlands
The new study measured methane emissions between 2018 and 2021 from hundreds of potential sources, based on data from the Sentinel-5P satellite.
Satellites detect methane by measuring the absorption of specific wavelengths of infrared light that are unique to methane molecules, acting like a ‘fingerprint’.
A location was classified as a ‘persistent emitter’ if levels of methane were consistently higher than the surrounding area.
Overall, the top methane emitting region was South Sudan’s natural Sudd wetlands, with emissions of 4.5 million tonnes per year.
Wetland habitats are filled with waterlogged soils and permafrost, which is what makes them sizable carbon sinks – meaning they store locked away CO2.
But as a warming climate causes wetland soils to warm or flood, the carbon is released into the atmosphere as methane.
The biggest anthropogenic (human-made) source, and the second-biggest overall, was from the oil and gas fields on the west coast of Turkmenistan.
This site emits 3.5 million tonnes of methane per year from oil and gas, which form a key part of Turkmenistan’s economy.
Methane is a potent greenhouse gas responsible for more than 25 per cent of the global warming we are experiencing today. Pictured, global atmospheric methane concentration 2021 average
Data from the Copernicus Sentinel-5P satellite (pictured) was used to study and estimate methane emissions around the world
The west coast of Turkmenistan is an area dominated by oil and gas infrastructure. Pictured, oil refinery in Turkmenbashy, Turkmenistan, on a shore of the Caspian Sea is seen in this July 1997 file photo
Liaoning (pictured) and Shanxi provinces in China are known rice- and coal-production areas
Third on the list is Ibera in Argentina with 3.3 million tonnes also from wetlands, followed by Liaoning in China with 3.3 million from ‘other anthropogenic sources’.
Other anthropogenic sources includes landfills, wastewater, digestive gas from ruminant animals such as cattle, sheep and goats, as well as manure, rice and energy buildings.
Next on the list are three coal fields in Shanxi province in China followed (Shanxi 1, 2 and 3), with emissions of 2.6 million, 2.6 million and 2.4 million, respectively.
Bangladesh’s capital Dhaka and Russia’s Kuznetsk Basin both account for 2.4 million – from ‘other anthropogenic sources’ and coal, respectively.
Rounding out the list was the Permian Basin, the US’s highest producing oil field, spanning the border between Texas and New Mexico, with 2.2 million.
Overall, the study identified 217 locations where methane is emitted – 7.8 per cent by coal, another 7.8 per cent by oil and gas, 30.4 per cent by other anthropogenic sources like landfills or agriculture, 7.3 per cent by wetlands, and 46.5 per cent by unknown sources.
The study, published in Atmosphere, Chemistry and Physics, focused solely on sources that emit methane gradually over time – on a continuous, ‘persistent’ basis.
‘The aim was not to identify specific events where methane is only released for a short period of time,’ said co-author Michael Buchwitz, senior scientist at the University of Bremen, Germany.
Three coal fields in Shanxi, China (pictured) are on the list. The Shanxi province is a known methane source region with emissions resulting primarily from heavy coal mining activity
The city of Dhaka in Bangladesh (pictured) emits 2.4 million tonnes of methane per year from ‘other anthropogenic sources’, which may include landfills, wastewater, digestive gas from ruminant animals such as cattle, sheep and goats, as well as manure, rice and energy buildings
Russia’s Kuznetsk Basin also emits 2.4 million tonnes of methane per year but from burning coal for energy. Kuznetsk is one of the largest coal production areas worldwide
Satellites detect methane by measuring the absorption of specific wavelengths of infrared light that are unique to methane molecules, acting like a ‘fingerprint’
‘Instead, the aim was to identify sources that emit almost continuously during the four years that were analysed.
‘This includes natural sources such as wetlands, but also coal mining areas or large oil and gas fields.’
Methane has a more powerful warming effect than CO2, although it has a much shorter duration in the atmosphere before it decomposes.
Over a 20-year timescale, each kilogram of methane emitted has a global warming potential more than 80 times more potent than CO2.
Until 1850, methane levels were recorded at between 680 and 790 parts per billion, or ppb, according to data from NOAA Global Monitoring Laboratory.
But in the past decade, methane levels in Earth’s atmosphere have reached almost three times that to more than 1900 ppb.
‘A comparatively small number of highly emitting persistent methane sources are responsible for a large share of global methane emissions.
‘The identification and quantification of these sources, which often show large uncertainties regarding their emissions or locations, are important to support mitigating climate change.’
