Paths carved into boreal peatlands for oil and gas exploration could be speeding up climate change: study

Thousands of lines carven into Canada's circumboreal peatlands for oil color and gaseous state geographic expedition could be speeding up climate change, suggests a new study from University of Waterloo researchers.

Known as "seismic lines," they have been carved through the forests of B.C., Saskatchewan and especially Alberta for accommodating oil and gas surveying equipment, and are also found in other oil-producing countries.

There are about 345,000 kilometres of seismic lines crossing boreal peatlands in Alberta alone, which would go around the Earth nine times if laid end-to-end, representing a massive chunk of forest that has been damaged.

Previous research had indicated that many seismic lines are not regrowing and might have uncounted methane emissions. This study aimed to confirm those suspicions with field measurements and lay the groundwork for more research.

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Researchers collected field measurements of methane at three peatland sites by seismic lines in the Peace River region of Alberta, a centre of the oil and gas industry. Two seismic lines were surveyed at each site, and then compared with neighbouring areas of undisturbed peatland.

The study found that methane emissions from these lines are almost three times higher in bogs and nearly two times higher in fens when compared with the undisturbed peatland. Both bogs and fens are carbon-rich peatlands but differ in their water sources and the type of plants and trees they support.

"We have these same seismic lines in use in the U.S., in Russia, in Scandinavia," said lead author Percy Korsah, postdoctoral scholar in the Wetland Soils and Greenhouse Gas Exchange Lab at the University of Waterloo in Ontario.

"[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."

Methane is a potent greenhouse gas that, even though it's not as long-lasting, has 80 times the heat-trapping power of carbon dioxide and is responsible for a third of global warming.

Creating seismic lines involves sending bulldozers and excavators through forests, removing trees and vegetation and compressing the peatland surface underneath. This creates the waterlogged conditions in which decomposition releases large amounts of methane.

The change in the soil and water flow also affects which plants can grow back, and, as Korsah found, those lines were not growing back to what they were before.

In a picture from one location in the study, Korsah stands in front of a site that was cleared more than 50 years ago. The plants have still not regrown.

Researchers have been concerned about the seismic lines for a while now, especially because they're so ubiquitous on the landscape. But companies that build these lines generally don't have a legal requirement to restore them afterward.

Still, concern over how these lines were affecting native caribou led the Alberta government to start a restoration program in 2017. The province has planted 2.8 million trees as part of its efforts to restore the lines and protect habitats, and oil and gas companies have contributed to the effort.

The major oilsands companies are part of a research group looking into the impact of seismic lines, and the provincial government has signed several funding agreements with energy companies on restoration projects.

The new paper, however, suggests these lines need to be restored to slow down climate change, as well.

"The study is also important because it reports specifically on methane, which compared to carbon dioxide, is a much more powerful greenhouse gas. But for a number of reasons methane is not often measured and this has created a big knowledge gap," said Peter Morse, research scientist at Natural Resources Canada, via email.

Morse said baseline studies like this one are important because they can help improve estimates of methane emissions in the future, but collecting the required data is a challenging process. Other jurisdictions in Canada outside Alberta don't even have complete information about where seismic lines are, and conducting field research in these remote areas is difficult.

"Future studies will have to investigate methane emissions over a full year, for a number of years, and at a range of sites that have different ages and types of peatlands and permafrost environments," he said.

In a statement, Environment and Climate Change Canada said the study's data "will help improve the accuracy of tracking greenhouse gases related to landscape disturbances such as seismic lines." 

Bin Xu is a peatland restoration researcher at the Centre for Boreal Research at the Northern Alberta Institute of Technology. He says that techniques to restore peatlands damaged by oil and gas activity have improved, but the scale of the seismic lines makes the work difficult.

"We don't have an unlimited amount of money and machinery to treat every single line. So we need to be smart and strategic about how to prioritize areas so that we get the most return on that investment into restoration," he said.

Xu said that not all seismic lines are emitting methane the same way as the sites measured in the new Waterloo study. Because of the many thousands of kilometres of lines scattered across Canada, it's important to find which lines are the worst offenders.

Peatlands present a special challenge because they take a long time to grow. The peatlands in Alberta grew over centuries, he pointed out. 

Older seismic lines, also called legacy lines, are up to 10 metres in width, but because of growing concern over their impact, the industry moved to lower-impact 1.5- to five-metre-wide lines about three decades ago. The Waterloo study, however, says it's unclear if that's enough because surveyors need a denser network of the thinner lines to collect their data, meaning more lines are created.

Korsah said that expanding peatland restoration will reduce the methane emissions, which is crucial for fighting climate change — but "you cannot necessarily get it back to the original state."

The way forward, he said, is to encourage the industry to use smaller and fewer lines, or technology that eliminates their need entirely.

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