Until fairly recently, producing oil from oil sands was viewed as a sort of ‘a last resort’ for the petroleum industry, because of the complexity of the mining techniques required. Bitumen – which is a highly viscous form of crude oil – can’t be processed in the same way as ‘conventional’ oil and gas, which makes it more expensive to produce. As oil prices have increased, unconventional sources like oil sands have become more commercially viable, to the point at which they now play an important role in the world’s petroleum industry. By some estimates, oil sands may account for ~6% of the global oil supply by 2040.
But, like all extractive industries, this comes at a significant cost to the environment.
Take the Athabasca oil sands in Alberta, Canada. As the “largest deposit of crude oil on the planet,” they’ve been commercially mined since the late 1960s, but it’s in the past 25 years that activity has really picked up pace. It’s been described as the “most destructive industrial project on Earth”, and for good reason. Open-pit mining there involves the removal of huge swathes of boreal forest and muskeg (peat bog), which fragments the landscape, destroying key habitats for Caribou and other animals. Leaks from storage tanks have entered local waterways, depositing toxic levels of heavy metals, acids and particulates into the Athabasca River and its tributaries, significantly impacting bird, fish, and human populations.
Indigenous communities – namely, members of the Athabasca Chipewyan First Nation – have been sounding the alarm on this for decades, calling these large-scale mining operations “a slow industrial genocide.” The most recent leak was so significant (5.3 million litres of liquid waste) that community leaders advised all members to dispose of any game or fish they’d harvested in previous months.**
Turning oil sand into crude oil also produces huge quantities of greenhouse gases. Back in 2009, a CERA report estimated that emissions were “5 to 15 percent higher than the average crude refined in the United States.” But new research led by environmental engineers at Yale shows that the real figures are even worse than we could have imagined.
Writing in this week’s edition of the journal Science, they report on their use of a research aircraft (the National Research Council of Canada’s Convair-580) to fly a suite of gas sensors above the Athabasca oil sands. In 30 flights over 17 mining and extraction facilities, they carried out “the first carbon closure experiments for any industrial source”, measuring and mapping out emissions from the region, and compared them to those reported by industry.
When it comes to industry monitoring and reporting, the term ‘emissions’ has historically referred to a specific group of small hydrocarbons known as volatile organic compounds (VOCs). This has been for two reasons; one, the assumption that these molecules represent the majority of gas species emitted (in terms of the quantity of carbon present, and/or the reactivity), and two, the ease with VOCs can be measured. In reality, anthropogenic carbon emissions – particularly those produced by the oil and gas sector – are complex, incorporating a wide range of molecular sizes and chemical behaviours. VOCs don’t tell the complete story, and the Yale researchers proved that.
The main tool they used was a pair of laser-based gas-sensing instruments called Cavity Ring Down (CRD) spectrometers. You can learn more about how they work here, but in brief: the gas sample you’re interested in is collected in a cavity flanked by two (sometimes three) highly-reflective mirrors. When a short laser pulse is sent into the cavity, it continuously bounces between the mirrors, passing through the gas as it does so. Because every gas (e.g. CO, CO2, and CH4) has its own unique absorption spectrum, monitoring how the laser light changes as it passes through the gas allows you to identify the gas. If the sample includes a mixture of different gases, the system can determine the relative concentration of each one.
This experiment used a pair of CRDs because the goal was to measure all of the carbon species present in the air samples – not just VOCs. They did this by adding a platinum catalyst to one CRD, but not the other. The catalyst converted all of the carbon-containing gases in that sample to CO2; the other sample was left unconverted. By comparing the measurements from both CRDs, they could determine the ‘total gas-phase organic carbon’ in the air, measuring those gases important to air quality.
They also measured levels of nitrogen oxides (NO, NO2 and NOy) downwind from the facilities and at different altitudes, to identify any additional chemical reactions that might have taken place. And, to supplement all of these in-flight measurements, they carried out detailed lab analysis of the collected samples.
They found that measured VOCs account for just a fraction (between 6 and 31%) of total measured organic carbon above major oil sand facilities. And most importantly, they measures the total carbon emitted at every site. At the three highest-emitting sites, annual emissions were estimated to be ~200,000 to 500,000 tonnes of carbon per year. The sum of annual emissions across all of the measured sites was 1.59 million tonnes of carbon per year, making them 20 to 64 times greater than those reported on official inventories (which are based on standard monitoring techniques).
To put that into context, they write that this is “approximately equivalent to the VOC emissions reported for the sum of all anthropogenic sources in Canada’s Air Pollutant Emissions Inventory.” In other words, it is about the same as the rest of Canada’s emissions combined, e.g. from road transport, domestic wood fires, and all other industries. It is also far more emissions than is produced by all sources in the city of Los Angeles (which emits ~0.1 million tonnes of carbon per year in the South Coast Air Basin).
Amongst other things, these findings demonstrate that standard monitoring techniques do not sufficiently capture all of the emissions produced by facilities like these, and that regulators don’t have a full understanding of air pollution across the region. Speaking to the Canadian Broadcasting Corporation, Dr Jeffrey Brook, an air quality expert who was not involved in the study, said it shows "that there's a whole class of air pollutants that are being released in large quantities that are largely, if not completely, being excluded from official reporting."
This study makes the scale of the problem very, very clear. Let’s see if anything changes as a result.
** To learn more, please read this fantastic 2021 article by Nicholas Kusnetz, explore this interactive feature from The Guardian, and watch ‘Killer Water’, a heart-breaking, compelling and freely-available documentary by Brandi Morin and Geordie Day.
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