Coal mines seen belching worst Australia methane cloud this year

Most of Australia’s coal mines are in the Hunter Valley (pictured), Bowen Basin and Surat Basin regions. (Image: Max Phillips (Jeremy Buckingham MLC) | Flickr.)

The most severe cloud of methane detected in Australia in more than a year was spotted last month by satellite over one of the country’s top coal producing regions.

The Oct. 17 plume was observed over the Bowen Basin in Queensland state and had an estimated emissions rate of 76 metric tons of methane an hour, according to Kayrros SAS, which analyzed observations from the European Space Agency’s Sentinel-5P satellite. The geoanalytics company said that given the high concentration of mines in the plume’s vicinity and its shape, it could have originated from multiple sources. 

“Intermittent methane releases from underground mines, such as the ones mentioned, are a part of normal operations,’’ Australia’s Department of Industry, Science, Energy and Resources said in an emailed response to questions. The agency is implementing a methane accounting system using Sentinel data “to assess the implications of methane releases, such as the one observed in the picture provided,’’ to help track emissions.

The nation is facing growing global criticism from climate activists who say it isn’t doing enough to cut emissions. Australia won’t join a global effort led by the U.S. and European Union to curb methane emissions, Energy Minister Angus Taylor said before the start of the COP26 global climate conference now underway in Glasgow. The initiative, which includes 100 nations, aims to curb methane emissions at least 30% from 2020 levels by the end of the decade.

Methane has more than 80 times the warming impact of carbon dioxide over the short term. Halting intentional releases and accidental leaks could do more to slow climate change than almost any other single measure. Cheap technologies to mitigate coal mine emissions are widely available, according to climate research group Ember, while oil and gas companies can often profit from emissions reductions by selling the corralled methane as natural gas.

Higher methane emissions can result in part due to a region’s geography, and older and deeper coal seams typically emit more gas.

For every ton of coal produced in the Bowen Basin region, an average of 7.5 kilograms of methane is released, a Kayrros analysis found earlier this year. That’s 47% higher than the average global methane intensity estimated by the International Energy Agency, the company said at the time.

“The Department of Industry, Science, Energy and Resources accepts that the Sentinel satellite data is a useful source of information that needs careful consideration,” the Australian agency said in its statement. But the department said that it believes “it is premature to use the satellite data to quantify emissions in a reliable way. ”

If the October release lasted an hour at the rate estimated by Kayrros, it would have the same short-term climate impact as the annual average emissions from more than 3,700 U.K. cars. The plume was the most severe in Australia since a release detected in August last year, that was about 170 kilometers (106 miles) to the north, according to the Kayrros analysis of ESA data.

Scientists are just beginning to pinpoint the biggest sources of methane and existing satellite observations aren’t globally comprehensive. Cloud cover, precipitation and varying light can impact observations and the orbitals also have difficulty tracking releases over water.

(By Aaron Clark)

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