Wednesday, 14 March 2012

The effects of oil sands mining on wetlands in northern Alberta.

Oil sands are sandstones rich in heavy petroleum fractions (bitumen), these can be worked for oil by strip mining and separating the bitumen (which has roughly the consistency of molasses) from the sand by a process known as steam-assisted gravity draining, which involves using super-heated steam to liquify the oil. This is much more expensive than conventional methods of oil production, and has only recently become a financially viable option as world oil stocks have dwindled and oil prices have risen. It also produces three to four times as much carbon dioxide (CO₂) as conventional oil extraction methods, which, when combined with the habitat loss associated with strip mining, makes it extremely unpopular with environmental groups.

Alberta has approximately 4750 km³ of oil sands deposits in boreal forest available for strip mining, 99% of which are already leased, despite widespread opposition from environmental groups. The group Oil Sands Truth describes this project as 'largest industrial project in human history and likely also the most destructive' and likely to become 'single largest industrial contributor in North America to Climate Change'. The group Dirty Oil Sands describes the industry as the 'Canadian oil sands disaster' and 'the world’s most harmful type of oil for the atmosphere'. Conversely the Government of Alberta and companies in the industry talk about the economic importance of oil sands development, and the environmentally responsible way in which the reserves are being developed.

An oil-sands development in Alberta. National Geographic.

In a paper published in the Proceedings of the National Academy of Sciences on 12 March 2012, Rebecca Rooney, Suzanne Bayley, and David Schindler, all of the Department of Biological Sciences at the University of Alberta, attempt to quantify the effects of the oil-sand industry on the wetlands of Alberta, and the wider environmental impact of these effects.

Rooney et al. were able to study pre- and planned post-operation vegetative cover at only four of the ten mining operations in the area (the Horizon, Jackpine, Muskeg, and Kearl mines) the others declining to comply. This represented 42% of the total area earmarked for oil-sands extraction.

Vegetation cover at the four mines prior to the extraction operation. From Rooney et al. (2012) supplemental information.

Rooney et al. found that the environment in the effected areas will change substantially, most notably in the loss of 124 km² of peatland and an increase in upland forest of 150 km² of upland forest, primarily plantation conifers. They calculate that if a similar pattern is followed at the other six mines then a total of about 300 km² of peatland will be lost.

Planned restored vegetation after the mining operations are complete. From Rooneyet al. (2012) supplemental information.

The University of Alberta team note that while the mining operations are obliged to return the sites to a 'natural state', this does not have to be the same state as prior to extraction, and that Alberta has no official state policy requiring the replacement of wetlands. They also observe that it would be far easier to restore well-drained upland forest than peatlands, due to the way in which the mining operation will alter the overall landscape.

Boreal forests, and in particular peatlands within them, are major global carbon sinks. Rooney et al. calculate that the loss of 150 km² of peatland will lead to between 4.8 and 19.9 million tonnes of Carbon Dioxide (CO₂) being discharged into the atmosphere. Scaling this up across all the concessions gives a total figure of between 11.4 and 47.3 million tonnes of CO₂.

Based upon this Rooney et al. raise concerns that oil-sands sourced hydrocarbons will be far more CO₂ intensive than currently anticipated, and reject industry claims that extractors will 'return the land we use - including reclaiming tailings ponds - to a sustainable landscape that is equal to or better than how we found it' and 'will be replanted with the same trees and plants and formed into habitat for the same species' as 'greenwash'.

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