Reclamation following open-pit oilsands mining does not account for the massive loss of carbon stored in destroyed peatland, according to a new study released last week, meaning carbon emissions calculations to date could be vastly underestimated.
The study, led by the University of Alberta’s Rebecca Rooney and co-authored by Suzanne Bayley and David Schindler, says oilsands reclamation sites do not provide the same ecosystem services they did before mining, such as providing carbon storage capacity, and accuses oilsands companies of “greenwashing” in relation to their claims of habitat restoration.
“We quantified the wholesale transformation of the boreal landscape by open-pit oilsands mining in Alberta, Canada to evaluate its effect on carbon storage and sequestration. Contrary to claims made in the media, peatland destroyed by open-pit mining will not be restored,” states the report.
While land reclamation is required following open-pit mining in Alberta, regulations do not require restoration to replicate previous land cover. As a result, restored habitat may result in a total landscape transformation – the net effect of which has not been assessed.
The study calculates over 29,500 hectares of peatland habitat are being destroyed and replaced with upland forest and tailings storage lakes, leading to the release of huge quantities of carbon once stored underground, along with decimating future storage capacity. The authors estimate that 65 per cent of the oilsands region consists of peatland ecosystems.
“Landscape changes caused by currently approved mines will release between 11.4 and 47.3 million metric tons of stored carbon and will reduce carbon sequestration potential by 5,734–7,241 metric tons C/y (carbon per year),” stated the study’s authors.
Consequently, the scientists report, calculations of carbon emissions from oilsands development to date have been well below the reality. Emissions from bitumen mining tally up to over 70,000 tons of carbon dioxide released into the atmosphere per day, according to 2010 mining levels of 1,142,000 barrels per day. Tacking on carbon emissions resulting from peatland loss would add an estimated seven years’ worth of carbon emissions by mining and upgrading at those levels.
“These losses have not previously been quantified, and should be included with the already high estimates of carbon emissions from oilsands mining and bitumen upgrading,” said the report. “A fair evaluation of the costs and benefits of oilsands mining requires a rigorous assessment of impacts on natural capital and ecosystem services.”
Dr. Mike Waddington, an expert in peatland ecosystems at the McMaster Centre for Climate Change, said the hydrology of peatlands makes them ideal carbon storage sites.
“Peatlands have a water table at or near the surface making for highly reduced conditions (saturated soils) that keeps carbon decomposition low, allowing these ecosystems to accumulate soil carbon over centuries to millennia,” he said. “By removing these ecosystems from the landscape, that important ecosystem function is lost.”
Scientists with oilsands companies Syncrude and Suncor are currently researching methods of reclaiming peatlands on the oilsands landscape after mine closure, which would require peat from donor natural peatland to be transferred to the reclaimed peatland. This has successfully been carried out in eastern Canada, where peat is mined for gardening and agriculture.
While Waddington supports the idea of peat restoration, he said the chances of it being carried out as successfully in the oilsands region, which has a much drier climate, are low.
“The post-mining oilsands landscape is a much larger challenge and the climate doesn’t help either,” he said. “Much of central Alberta is the in boreal plains where evapo-transpiration exceeds precipitation, and keeping these ecosystems wet is essential for them to develop and persist on the landscape.”
Dr. Merritt Turetsky, who studies the ways plants assist in regulating the climate, said the worldwide loss of peatland, which has a net cooling effect on the atmosphere, means giving up thousands of years of natural climate management.
“Once Alberta’s peatlands are disturbed by mining, most (if not all) of the carbon stored in these peat soils eventually will make its way back to the atmosphere,” she said. “This not only represents a release of old carbon to the atmosphere, but also removes carbon sink potential from the landscape. In other words, land use will alter how ecosystems regulate the Earth’s climate system for decades if not centuries to come.”
Rooney, Schindler and Bayley conclude that without baseline environmental studies available, assessment of reclamation projects is vital to determine the ongoing impacts on natural capital and biodiversity.
“No large-scale oilsands reclamation project has undergone independent evaluation, and thus the ultimate success of closure plans remains uncertain,” they said. “To fairly evaluate the costs and bene?ts of oilsands mining in Alberta, impacts on natural capital and ecosystem services must be rigorously assessed.”