Global researchers have been worried about global methane levels for some time. The gas drives global warming much faster than carbon dioxide (CO2). And for some time now, scientists have seen an increase in the atmosphere.
The causes are the thawing permafrost in the cold regions of the world. Here biomass from dead plants is decomposed by microorganisms, producing CO2 and methane. Another reason for higher gas emissions could be the increased production of shale gas - methane is the main component of natural gas.
A new study now reveals the large amounts of methane that can escape into the atmosphere if a gas source breaks down. For some time now, scientists have also been using satellite data from the European Space Agency Esa to detect and measure leaks and other hotspots.
A team led by Sudhanshu Pandey from the Netherlands Institute for Space Research in Utrecht has evaluated the recordings of a known leak. This occurred at a natural gas production site in Ohio in February 2018. Exxon Mobil says that exactly how much methane was released at the time was unknown, reports the "New York Times".
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The new study provides more precise data. According to the study, approximately 120 tons of methane per hour have escaped from the source within 20 days, the researchers write in the "Proceedings of the National Academy of Sciences".
Based on the hourly value, this is twice the amount of the largest known leak in the history of American gas production: In 2015, tons of methane flowed from an underground storage facility in Aliso Canyon in California. However, the total released at that time was larger than that in Ohio.
Around 100,000 tons of methane were released in California within 112 days. The Ohio leak could have been as little as 60,000 tons, the researchers estimate. This would correspond to around a quarter of the total annual methane emissions from Ohio's oil and gas production.
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Methane (CH4) is considered a climate-damaging greenhouse gas, the impact of which on the global rise in temperature has long been underestimated. It drives global warming much faster than carbon dioxide - even if less methane than CO2 is released. Methane occurs naturally and generates less CO2 than coal when burned. But if the colorless and odorless gas gets directly into the atmosphere, it has a climate-damaging effect. It oxidizes to carbon monoxide and later to carbon dioxide.
According to the researchers, the current study shows what is possible with satellite data in methane monitoring. In the meantime, very regional events could be evaluated from space. Researchers can obtain data on global methane concentrations from the Tropospheric Monitoring Instrument, or Tropomi for short. It hovers around the world on board the Sentinal-5P earth observation satellite. In addition to methane, the ozone, carbon monoxide or sulfur dioxide content in the atmosphere can also be measured.
Fracking under suspicion
When it comes to gas production, researchers are particularly concerned about the controversial fracking technique. It is suspected to be involved in the increased release of methane. The United States and Canada in particular are using the process to access previously inaccessible natural gas deposits. In fracking, the shale is first drilled and then liquid is pressed into the rock under high pressure. Cracks occur in the rock layer, through which the gas escapes and emerges at the borehole.
Only a few months ago, it was announced that the government of US President Donald Trump was working to relax environmental laws for the oil and gas industry. Accordingly, the plan of the US environmental protection agency EPA (Environmental Protection Agency) is to provide that methane emissions will be monitored less strictly in the future.
For example, companies currently have to equip boreholes, pipelines or storage facilities with complex technology to identify leaks from which the gas escapes and then to seal them.
