Some 345,000 kilometres of seismic lines generated by oil and gas activity scar Alberta’s boreal peatlands, and a new University of Waterloo study finds they’re emitting up to three times more methane than the undisturbed land around them.

Published in the journal Nature Communications Earth & Environment, the study reports on methane emissions from oil exploration survey paths running through two treed bogs in the Peace River region during the 2018-2019 growing season. Two paths from each bog were studied, along with two other seismic lines cutting through a treed fen in the same region.

Methane emissions from the seismic lines in the bogs were “almost triple”—261% to 308%— what was measured in adjacent, undisturbed areas. Seismic lines cutting through the fen were found to emit nearly twice as much methane (176%) as adjacent undisturbed fen.

The main difference between a bog and a fen is that the former is mainly fed by rainwater, while the latter depends on groundwater. This distinction produces differences in water table levels and ground cover, which in turn affect carbon sequestration levels and methane production rates.

Methane is an extremely potent greenhouse gas, with one tonne of the hydrocarbon causing about the same warming as around 80 tonnes of carbon dioxide over the crucial 20-year span when humanity will be scrambling to get climate change under control.

Boreal peatlands are powerful long-term carbon sinks, but also powerful sources of methane emissions when they’re disturbed.

The existing network of seismic lines in Alberta could, laid end-to-end, “wrap around the Earth nine times,” which gives a measure of their potential impact on methane emissions, writes Phys.org.

“We have these same seismic lines in use in the United States, in Russia, in Scandinavia,” lead author Percy Korsah, postdoctoral scholar with the Wetland Soils and Greenhouse Gas Exchange Lab at the University of Waterloo, told CBC News.

“[In] these lines, we are now finding out that emissions have doubled and tripled. So if you look at the scale, then we are in trouble.”

Korsah and his team measured methane emissions from so-called “legacy lines,” heavily used by the fossil industry 50 years ago. Created by bulldozers, these can be up to 10 metres wide and have been implicated in the decline of woodland caribou as their treelessness facilitates the movement of the herds’ chief predators: wolves.

The heavy equipment also compresses soil in the peatlands, harming drainage and thereby creating waterlogged conditions that can accelerate methane release.

Such seismic lines have been very slow to recover, with some remaining treeless 50 years on.

The researchers also measured emissions from narrower seismic lines introduced by the oil and gas industry roughly 30 years ago in response to environmental concerns. These are 1.5 to 5 metres wide and typically cut by chainsaws.

Across all the research plots, the seismic lines were “significantly warmer and wetter” than adjacent undisturbed areas, thereby “providing ideal conditions for increased methane emissions at all sites,” the study found.

The loss of tree and shrub cover “potentially accounts for the observed significant temperature differences where the average temperatures on all lines at measured depths were at least 1 °C warmer than the surrounding peatland,” the study authors write.

The generally compacted state of soil across all seismic lines also raised water tables.

“These findings justify concerns raised by previous studies with regard to under-reporting of methane emissions in response to boreal peatland disturbance arising from resource exploration activities,” the study says

“In this moment, when there is excitement about profits from resource development projects, we need to ensure that our decisions fully consider the environmental impacts,” study co-author Maria Strack, Canada Research Chair in Wetland Climate Solutions at the University of Waterloo, told Phys.org. “Greenhouse gas emissions and the costs of restoration could make these projects no longer viable or practical.”