A multi-disciplinary panel of experts assembled by the Canadian Council of Academies has released a major study on the environmental impacts of shale gas development in Canada. The Council is an independent research organization of the Royal Society of Canada, the Canadian Academy of Engineering and the Canadian Academy of Health Sciences. The Council is funded by the Canadian federal government.
The Study was commissioned in 2012 by the federal Environment Minister to provide an evidence-based and authoritative assessment of the following question:
What is the state of knowledge of potential environmental impacts from the exploration, extraction and development of Canada's shale gas resources, and what is the state of knowledge of associated mitigation options?
Further to this question, the Council was also asked:
- Based on existing research, what new or more significant environmental impacts may result from shale gas extraction relative to conventional gas extraction?
- What are the science and technology gaps in our understanding of these impacts and possible mitigation measures/strategies, and what research is needed to fill these gaps?
- What monitoring approaches could inform the effective understanding and mitigation of impacts, what is the current state of the art and state of practice for such monitoring, and what science and technology gaps may act as barriers to effective monitoring?
- What technical practices exist to mitigate these impacts, and what are international best practices? What science underpins current policy or regulatory practices internationally?
The Study does not make recommendations, but rather presents observations and conclusions on what is known and not known about the environmental impacts of shale gas development, the options to mitigate them and opportunities for research to fill gaps in monitoring and understanding.
The Study focused on:
- water (groundwater and surface);
- greenhouse gas emissions;
- land impacts and seismic events;
- human health; and
- monitoring and research.
The Study calls for more research on the environmental impact of shale gas development in Canada. The Study concludes:
- In nearly all instances, shale gas extraction has proceeded without important environmental baseline data being collected (e.g. nearby groundwater quality). This makes it difficult to identify and characterize environmental impacts that may be associated with (or incorrectly blamed on) this development.
- There is a paucity of peer-reviewed articles in the scientific literature. The reasons include the fact that large-scale shale development is a young industry (some 20 years old in the United States and only half that in Canada), that the industry has kept some information proprietary (in part because technologies are evolving rapidly and are still being tested), and that U.S. federal legislation only indirectly regulates the chemical additives used in hydraulic fracturing and therefore industry has not had to monitor their impact.
- A major environmental concern regarding shale gas development - regional groundwater contamination - hinges on the flow of fluids in low permeability but commonly fractured geological strata. However, because past scientific interest has largely focused on high permeability rocks (aquifers and petroleum reservoirs), fluid flow in low permeability rocks is poorly understood. Thus, the basic scientific knowledge needed to evaluate potential risks to groundwater on the regional scale is largely lacking.
- In areas where peer-reviewed studies are available, they do not necessarily agree. For example, there is a substantial range of expert opinion on the extent of fugitive methane emissions from shale gas development.
- Some of the possible environmental effects of shale gas development, such as the creation of sub-surface pathways between the shale horizons being fractured and fresh groundwater, gas seepage from abandoned wells, and cumulative effects on the land and communities, may take decades to become apparent. Similarly, monitoring information, and information on the effectiveness of mitigation measure, take time to acquire and assess.
- Much if not most of what can be said about the potential environmental impacts of shale gas development depends on assumptions made about the location, pace, and scale of development, all of which will be influenced by future natural gas prices, government policy, and technological improvements. None of these can be predicted with certainty.