Australasian Science: Australia's authority on science since 1938

Increased Emissions in Coal Seam Gas Fields

Atmospheric methane and carbon dioxide concentrations are higher at coal seam gas fields in the Darling Downs and northern NSW, according to research published in Water, Air and Soil Pollution.

However, study co-author Prof Isaac Santos of Southern Cross University admits that one of the major issues with attributing the elevated gas concentrations to coal seam gas mining is the lack of baseline studies. “From our data we cannot conclusively say that the elevated concentrations are due to CSG mining activities as we have no information about the area before the commencement of CSG mining,” he says.

Nevertheless the study's lead author, Dr Damien Maher, says there were some clues to where the methane and carbon dioxide was originating. “We also measure the carbon stable isotope ratios of the gases, which is like a chemical fingerprint,” he says. “This gives us insight into where the gases came from and how they were formed. For example, in the Darling Downs the methane and carbon dioxide can be coming from sources other than CSG, such as wetlands, feedlots and vehicles.”

According to Maher, though: “The methane in the atmosphere of the Darling Downs gas field has a very similar fingerprint to methane in the CSG of the region. A portion of the carbon dioxide appears to be coming from the expansive water-holding ponds, which was something that surprised us.”

The researchers agree this is only a first step in determining the greenhouse gas footprint of the CSG industry in Australia. “While we know that there are some leakages happening in the studied CSG field, we do not know the magnitude of these leakages, nor do we know if this is a consistent trend across all CSG fields in Australia,” said co-author Dr Douglas Tait. “These are areas of research we are actively pursuing.”