Assessing Climate Change Impacts on Water Availability for Oil Sands Development in the Athabasca River Basin

Activity Rationale

Canada’s large oil sands reserves are expected to bring the nation prosperity and energy security. Their importance is becoming increasingly prominent as the conventional oil reserves are depleted, and as a result of the current political tensions and the associated high oil price in the world. Oil production from the oil sands, however, requires large water volumes (three barrels water to one barrel of oil), and climate change impacts on water supply is an unappreciated but potentially serious threat to Canada's oil production.

Leader: Steve Grasby

The Topic

Map depicting size of the world's largest oil deposit (140,000 km2), located in the Athabasca region of Alberta, Canada. An estimated 180 billion barrels of oil may be recoverable.
Map depicting size of the world's largest oil deposit (140,000 km2), located in the Athabasca region of Alberta, Canada. An estimated 180 billion barrels of oil may be recoverable.
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The production of oil from oil sands involves the extraction of bitumen which requires a significant volume of water. In order to produce one cubic metre of synthetic crude oil from oil sands, it has been estimated that 2-4.5 cubic metres of water must be used. Currently, oil sands mining projects are licensed to withdraw 370 million cubic metres (2.3 billion barrels) of freshwater per year from the Athabasca River. However, production from this resource is expanding, and taking all of the planned mining projects into account, water withdrawal would increase to 529 million cubic metres (3.3 billion barrels) per year. Some stakeholders have argued that the Athabasca River does not have sufficient flows to sustain this withdrawal.

Under the Environmental Protection and Enhancement Act (EPEA), the province of Alberta requires that effective water conservation and protection measures be employed by oil and gas operators. A number of water conservation strategies are currently being utilized or researched, including:

  • The recycling or reuse of process water
  • The use of brackish or saline water from aquifers
  • The recapture and reuse of mining tailings water
  • Research into extraction and tailing technologies that would serve to reduce water use
  • Research into in situ bitumen recovery methods that use solvents, and are non-thermal, therefore not requiring water for steam
  • Investigation into cooperative withdrawal agreements between companies and water management strategies among oil sand operators

However, research has suggested that the climate is changing towards drier, warmer conditions, which could further limit the freshwater supply from the Athabasca River. Output assessments under various climate scenarios and research into climate change adaptation possibilities will be necessary to sustain both the freshwater resource and oil sands production.

Declining conventional oil supply

Declining conventional oil supply
Forecasting Canadian oil production

Forecasting Canadian oil production

   

Policy balancing act

It is clear that with the decline of conventional oil supplies in Canada, the type of oil supply that Canada will rely upon increasingly in the future has shifted to oil sands production. The production of oil in Canada presently requires a great deal of water. Recent research has been focussed on the establishment of realistic projections of water flows in Alberta, particularly in the Athabasca region where the largest oil deposit is located, in order to ascertain how much oil sands production can be sustained in the coming years to meet Canada's energy needs while at the same time protecting northern ecosystems.

The river discharge rates naturally fluctuate on decadal and century scale cycles, but since most records along the Athabasca River only date back 50 years, some cycles may be missed and therefore provide an inaccurate estimate of trends. Scientists have constructed models by integrating multiple observed cycles in river flow discharge.

 

Graph representing the potential for biased estimates of trends. In this case, a trend extrapolated over part of a cycle (yellow line) makes the declining trend appear more severe than if the trend was extrapolated over the full cycle (red line).
Graph representing the potential for biased estimates of trends. In this case, a trend extrapolated over part of a cycle (yellow line) makes the declining trend appear more severe than if the trend was extrapolated over the full cycle (red line).
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Extrapolating trends in river flow discharge rates from historical data. By using longer records from a wider region, a more precise picture of water trends can be obtained and used to plan for the sustainable use of water resources.
Extrapolating trends in river flow discharge rates from historical data. By using longer records from a wider region, a more precise picture of water trends can be obtained and used to plan for the sustainable use of water resources.
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Results

Establishing realistic projections of river flow in the Athabasca River basin is necessary to create adaptation strategies that will ensure the sustainability of this resource under future climate regimes, and to meet the economic and environmental goals of the region. However, projecting future conditions involves a level of uncertainty. To obtain better estimates, models commonly used to project future trends were analyzed for weaknesses before being used to predict future flows in the Athabasca River.

Estimating future climatic conditions often involves “trend analysis”, where historical data is analyzed to spot a pattern, or trend, in the data. The historical information is then used to forecast future trends, giving scientists and decision-makers an idea of what conditions could be expected under future climate regimes. Many hydrologic studies involving trend analysis have been used to make assessments of future water availability. However, research investigating the effects of natural climate variability on trend analysis suggests that oscillations (cycles) within the hydrologic cycle can misinterpret the true long-term trend, resulting in biased estimations of future trends.

Decadal and inter-decal oscillations are part of long-term natural variations in river discharge and climate variables. For example, well-recognized oscillations affecting the hydrologic cycle in North America include the El Niňo/La Niňa Southern Oscillation (3-8 year cycle) and the Pacific Decadal Oscillation (50-70 year cycle). Many climate cycles observed in the instrument record seem to have cycles of 45-60 years.

Diagram showing the impacts of oscillations on trend analyses. The main diagram shows a long-term climate record with prominent oscillations and a positive trend over time. Boxes (a) and (b) illustrate a misinterpretation of the true trend because the snapshot of data does not encompass an entire cycle, resulting in an exaggerated trend in (a) and a negative trend in (b). In (c), a 1 ½ cycle length gives too great a trend increase because the record begins at a low point in the cycle (Chen and Grasby, 2008).
Diagram showing the impacts of oscillations on trend analyses. The main diagram shows a long-term climate record with prominent oscillations and a positive trend over time. Boxes (a) and (b) illustrate a misinterpretation of the true trend because the snapshot of data does not encompass an entire cycle, resulting in an exaggerated trend in (a) and a negative trend in (b). In (c), a 1 ½ cycle length gives too great a trend increase because the record begins at a low point in the cycle (Chen and Grasby, 2008).
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The presence of climate cycles in datasets has been found to affect the statistical analyses of long-term trends in river flow. Following extensive statistical tests on real and simulated hydrological data, it was found that the length of the data record, the magnitude of the cycles, and the phase of the longest cycle had the most effect on trend analysis. Because of the prominence of 45-60 year climate cycles, trend analyses of records shorter than 60 years should be considered with caution.

Most records associated with flow of the Athabasca River are too short to make meaningful statements on long-term trends in historic flow. However, new methods of examining shorter term records are being developed. On-going research will use the wisdom gained from exploring trend analysis methods to assess river flows in the Athabasca River basin, allowing more realistic projections of water flow to be established.

Study Data

Long-term temperature and river discharge time series used for this activity are available from Environment Canada on the Adjusted Historical Canadian Climate Data (ADCCD) website. The datasets used for the paper Impact of decadal and century-scale oscillations on hydroclimate trend analyses were long-term annual maximum temperatures recorded at Calgary international airport and annual Bow River discharge recorded at the Calgary station.

Publications

Please note that subscriptions may be required to access some articles. To request a copy of publications, or for any more information, please contact Steve Grasby

Chen, Z. and Grasby, S.E. (2009). Impact of decadal and century-scale oscillations on hydroclimate trend analyses. Journal of Hydrology. GSC Contribution 20080499.

Chen, Z. and Grasby, S. E. (in press). Detection of decadal and interdecadal oscillations and temporal trend analysis of climate and hydrological time series, Canadian Prairies. Geological Survey of Canada Open File Report 5782

Grasby, S.E. and Chen, Z. (2008). Does Canada have enough water to meet future energy demand? CSPG Annual Convention, May 12-15, Calgary, AB.