Top 10 global methane emissions hotspots spotted by satellites

Methane is a potent greenhouse gas that plays a significant role in global warming, yet its persistent emissions often go unnoticed.

As we strive for a more sustainable and climate-friendly future, understanding the sources of methane emissions is crucial to predicting the ability of the Earth’s atmosphere to trap heat from the sun.

A recent study has identified the top 10 regions worldwide where methane is consistently released, whether from natural wetlands or human-driven activities like oil extraction and the burning of coal.

Investigating global methane emissions

Researchers analyzed data from hundreds of potential sources of methane. They relied on data from the Copernicus Sentinel-5P mission, which made it possible to estimate emissions at 217 potential locations.

Rather than focusing on “super-emitters” – typically oil and gas operations, coal mines, or poorly managed landfills that release large amounts of methane unpredictably – the study examined sources that emit methane consistently over time.

Detecting persistent methane sources

The research was guided by a new methane concentration dataset and an algorithm developed at the University of Bremen.

The university was involved as part of the ESA Climate Change Initiative Greenhouse Gas Project and the ESA Earth System Science Hub projects, Methane CAMP and SMART-CH4.

Claus Zehner, ESA’s Mission Manager for Sentinel-5P, highlighted the unique capabilities of the mission.

“Sentinel-5P is currently the only satellite that provides the feasibility to detect methane sources on a global scale and on a daily basis,” noted Zehner.

Spotting the persistent emitters

The experts analyzed methane concentrations at different locations between 2018 and 2021.

Any location where methane levels were consistently elevated, when compared to surrounding areas, was identified as a potentially persistent emitter.

“The aim was not to identify specific events, where methane is only released for a short period. Instead, the aim was to identify sources that emit almost continuously during the four years that were analyzed,” said Michael Buchwitz, senior scientist at the University of Bremen.

Wetlands and natural methane emissions

The analysis identified the Sudd wetland in South Sudan as the world’s largest persistent emitter of methane, at 4.5 million tons per year.

The Iberá wetland in Argentina is also a major emitter, with an annual production of 3.3 million tons of methane.

Microbes found in wetland soils and waters are often anaerobic and release significant quantities of methane as a result of their metabolic reactions.

Although this is a natural source of methane gas, it has meaningful consequences for global warming.

Human footprint from oil, gas, and coal

Anthropogenic activities were the cause of the remaining eight largest persistent sources of this heat-trapping gas.

The biggest anthropogenic emissions were from the oil and gas fields on the west coast of Turkmenistan, where an estimated 3.5 million tons of methane are produced each year.

Coal fields in China and the Kuznetsk Basin, in Russia, along with oil and gas fields in the U.S. (Permian and Delaware Basins) made up most of the remaining top 10 global sites where methane is emitted slowly and persistently, leaving a considerable footprint.

In addition, Dakha in Bangladesh and Liaoning in China produced significant amounts methane through other anthropogenic activities, including wastewater management, digestive gas from ruminant animals such as cattle, sheep and goats, as well as from manure and rice fields.

The importance of methane

Methane is the second most important greenhouse gas after carbon dioxide, as it contributes significantly to global warming.

Its concentrations have skyrocketed to almost three times the levels recorded in 1850, making high-emitting and persistent sources a serious concern for our planet.

Given that this gas has a greater warming effect than carbon dioxide, cutting methane emissions would be a crucial strategy in mitigating the effects of global warming.

It’s our task to tackle these persistent sources head-on, in order to reduce the level of methane emissions entering the atmosphere on a daily basis.

Addressing the methane challenge

Identifying the locations of the world’s most important persistent methane emitters is just the first step. Managing or reducing these emissions will require targeted strategies.

Unlike carbon dioxide, methane remains in the atmosphere for a short period of time only, but its warming potential is significantly greater. This potentially makes immediate reductions in emission highly effective in slowing climate change.

Governments and industries are increasingly prioritizing methane mitigation. The Global Methane Pledge, launched at COP26, aims to cut emissions by at least 30% by 2030, with over 150 countries committed to action.

Technologies such as satellite monitoring, leak detection in oil and gas operations, and improved waste management practices are crucial in reducing emissions of methane that arise from human activities.

Managing wetlands and methane emissions

For natural sources like wetlands, mitigation is more complex. While these ecosystems are vital for biodiversity and carbon storage, researchers are exploring ways to balance their natural methane output with conservation efforts.

Strategies such as wetland restoration, water management techniques, and microbial interventions could help optimize emissions without harming these critical environments.

With growing awareness and improved detection capabilities, policymakers and scientists now have the data needed to drive targeted action.

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Featured image: A study by the University of Bremen has identified 217 potential persistent methane source regions, estimated their emissions and created a global map of their distribution. The data was from the Copernicus Sentinel-5P satellite, taken over the four-year period 2018–2021. It identifies some of the major regions that emit methane on a persistent, continuous basis. Credit: ESA

The full study was published in the journal Atmosphere, Chemistry and Physics.

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