LEIGH SALES, PRESENTER: Coal seam gas, while controversial, is supposed to be environmentally clean. But a new scientific study raises serious doubts about the green credentials of the expanding coal seam gas industry, suggesting it's far dirtier than it claims. Peter McCutcheon reports.

PETER MCCUTCHEON, REPORTER: These scientists are searching for a missing but vital piece of information. Using new technology, they're trying to measure the amount of leaking methane in coal seam gas fields.

And their results so far are striking.

ISAAC SANTOS, SOUTHERN CROSS UNIVERSITY: We're talking about 3.5 times higher than expected.

PETER RAYNER, UNIVERSITY OF MELBOURNE: It's a very significant study in the Australian context.

PETER MCCUTCHEON: This work raises serious questions about one of the central premises of the entire coal seam gas industry: that it's a cleaner fuel with a vital role to play in curbing greenhouse gas emissions.

DREW HUTTON, LOCK THE GATE ALLIANCE: This study now points in the direction that we've been saying for a long time; this is a dirty polluting industry.

PETER MCCUTCHEON: Coal seam gas is booming across southern Queensland and is now expanding into NSW. The industry is pushing its economic benefits as well as its green credentials.

RICK WILKINSON, PETROLEUM PRODUCTION & EXPLORATION ASSN: When we compare it against the other options, primarily coal, it's up to 70 per cent less greenhouse gas emissions.

PETER MCCUTCHEON: But there's one critical element in this equation that we know very little about: how many greenhouse gas emissions leak into the atmosphere during the extraction process?, what the industry calls fugitive emissions.

PETER RAYNER: Fugitive emissions are emissions that escape from the intended process of production. So they're emissions that escape maybe through pipelines or from well heads or through the soil that aren't an intended part of the process of generating the natural gas.

PETER MCCUTCHEON: So in an attempt to measure these elusive emissions, researchers from the Southern Cross University took part of their laboratory into the field, around northern NSW and the Tara gas fields in southern Queensland.

ISAAC SANTOS: This is new technology so our specific approach of driving a car and taking readings on the go is new.

PETER MCCUTCHEON: This method allowed them to take many more samples than was previously available. As expected, their spectrometer recorded low atmospheric levels of methane outside the gas fields. But once they got near the gas wells, the picture changed quite dramatically.

ISAAC SANTOS: They're extremely high. They're some of the highest ever found anywhere. Those concentrations are higher than found in Siberia in some of the largest gas fields from Russia.

PETER RAYNER: It could be a one off. That's the problem with doing one study: we don't know. What we now need to do is to check firstly the same field as it evolves through its stages of production, and secondly, to see whether this is happening elsewhere.

PETER MCCUTCHEON: Carbon cycle scientist Professor Peter Rayner has studied the Southern Cross University data and agrees it raises some significant questions. He says the data suggests the methane came from under the ground, which could have serious consequences.

PETER RAYNER: The problem is that methane is a much more serious greenhouse gas than carbon dioxide. So every little bit of methane that you leak as you try and mine this stuff, process it or burn it, contributes much more than the carbon dioxide.

PETER MCCUTCHEON: And that's bad news for any industry operating under a carbon tax. But the industry's peak body, the Australian Petroleum Production and Exploration Association, says this is all highly speculative.

RICK WILKINSON: I think the study's incomplete. I think there's much more work that needs to be done before they can reach conclusions. ... Do I think that this would fundamentally change the industry? No. These are, as you said, very small amounts that we're working with here and even within the range that are being talked about, it would not fundamentally change the equation that says gas is better for the environment than coal.

PETER MCCUTCHEON: But those farmers and environmentalists who've been campaigning against CSG are asking why these sort of studies weren't done before the industry was given the green light.

DREW HUTTON, LOCK THE GATE ALLIANCE: Governments give them a big push, off they go, no preliminary research, no baseline studies, no precautionary principle applied, just let 'em loose on the environment and then do your studies a decade or so later.

PETER MCCUTCHEON: And on that point at least, these researchers agree. But with no baseline study, they admit it's difficult to assess the true significance of their findings.

ISAAC SANTOS: I think the take-out message is that we've gotta make sure we take samples before we change the way the environment is working. We found very high concentrations and we are now in a position what the hell that means.

PETER MCCUTCHEON: Should've this have been done 10 years ago?

RICK WILKINSON: I think 10, 15. The issue is now should we support ongoing development research? Yes, we should and that's what our position is.

LEIGH SALES: Peter McCutcheon there.

EDITOR'S NOTE (15 NOVEMBER): This report originally referred to or Drew Hutton as being from the Queensland Greens, he is, in fact, from the Lock the Gate Alliance, and the transcript has been changed to reflect that.