Queensland's coal seam gas industry now has more than 7000 wells. Credit:Saah Moles, Wilderness Society US regulators this year lifted their estimate of America's annual emissions of methane – the potent gas that makes up most of natural gas – by 13 per cent with leakage from the oil and gas industry largely blamed. While methane clouds have been detected near gasfields, it took a huge leak starting last October from a gas storage site near Los Angeles to grab media attention. Thousands were forced to evacuate their homes, with the leak venting almost 100,000 tonnes of methane over 16 weeks. Methane has as much as 100 times the warming impact of carbon dioxide over a 20-year period and the release was akin to adding 500,000 cars to the roads during the event, local media reported. While Australia's gas boom, particularly for coal seam gas, is of a much smaller scale than the US shale bonanza, many of the issues are identical. These include the lack of baseline studies to distinguish the impacts of drilling and fracking of wells from natural methane seepage.

CSG has its protesters now – before fugitive emissions are known. Credit:Andrew Quilty Closer to the surface The uncertainties around CSG in particular "are really very large", Professor Rayner said. "It's closer to the surface [than conventional gas] ... it's more dispersed, and the chances for something to go wrong are much higher," he said. The industry says just 0.02 per cent of the gas developed vents as methane to the atmosphere. Credit:Glenn Hunt

CSG operators such as Santos, Origin Energy and BG Group, say they have every incentive to limit leakage of the lucrative commodity from their lattice of CSG wells and pipelines. According to Santos' environmental impact statement (EIS) for its $25 billion Gladstone LNG project, fugitive emissions would only be 0.1 per cent for the CSG gasfields themselves. Total emissions were just 20,000 tonnes of carbon-dioxide equivalent last year across its entire business. LNG exports were worth $16.9 billion in 2014-15, APPEA says. Credit:Stephanie Kelly "Santos meets all its regulatory requirements around emissions," a spokesman said. "We monitor, independently audit and make this data publically available in our annual Sustainability Report." But a spokesman for Queensland's Department of Environment and Heritage Protection conceded that Santos's EIS "does not include provisions for a formal auditing process". However, the proponent is required "to document its proposed operations and how these will impact on the environment, which the department uses to "to inform the relevant permit conditions and requirements".

Chinchilla community members said the Condamine River has never bubbled with such frequency before CGS mining came to the region. Credit:Max Phillips Even without unanticipated leakage, the surge in CNG and its processing for export markets is set to play a big role in a forecast jump Queensland's greenhouse gas emissions. The government estimates that the state's emissions will surge 35 per cent between 2014 and 2030 even as Australia is aiming to cut them. Migratory emissions Researchers, though, say little is understood about how drilling and fracking may create conditions for leakage through the soil long after a well has been decommissioned. With more than 7000 CSG wells in Australia and headed towards tens of thousands, "the long-term, post-production fugitive [emissions] are certainly a sleeper issue," Professor Rayner said.

Dimitri Lafleur, a former geoscientist at energy giant Shell, said the industry has little idea of how much "migratory emissions" are making it to the surface. "With such a vast network and thousands of wells, it is very difficult to come up with an accurate number if you don't monitor on a regular basis," said Mr Lafleur, a PhD student at Melbourne University under Professor Rayner. "And given it is not a requirement to minimise fugitive emissions, why would you?" Mr Lafleur is part of a team commissioned by The Australia Institute to examine how big a problem such leakage is and how it might affect Australia's national emissions targets given the industry's rapid expansion. "No one knows what the baseline emissions are – from natural emissions from seeps, bores, for example – but I believe there is a chance that these emissions will become larger, with continued water extraction," he said. Companies remove huge amounts of water to get to the gas, depressurising the aquifers in the process.

'Social licence issue' Political opposition to CSG has come mostly from the Greens. Labor and the Coalition generally back developments in Queensland, but have mixed views of the sector in other states such as Victoria and NSW. NSW Greens MP Jeremy Buckingham became an internet sensation when he set the Condamine River in Queensland alight in April. Deputy Greens leader Larissa Waters, along with independent senator Gleenn Lazaus, has helped lead senate inquiries into CSG. "Coal seam gas and fracking wells and pipes leak like a sieve, and they could be just as bad for the climate as burning coal," Greens Senator Larissa Waters said. "As disused gas wells age and concrete casings break down, we risk further leaks for decades to come," she said. "No studies have systematically examined the deteriorations of old wells."

Fairfax Media sought comment from Environment Minister Greg Hunt and his Labor counterpart, Mark Butler. Gas produces as much as 77 per cent more energy per molecule of CO2 than coal. Professor Rayner said emissions issues with CSG had the potential to diminish public support for an industry already dogged with problems such as salt disposal, access to farmers' lands and interference with ground water. If CSG is not cleaner than coal, "the whole social licence issue is brought into question," Professor Rayner said. "It becomes quite serious."