Cumulative and Regional Assessment: A Perspective

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This edition of our Environment and Energy Bulletin is authored by Denise Mullen and guests authors Ward Prystay and Brian Yates of Stantec.

All human activities have effects on the natural environment and on the human environment (i.e., the social and economic aspects of society). As the population and economy grow, the environment is always changing. Many are familiar with the term cumulative impact or cumulative effects assessment (CEA) as part of the review processes for large projects — mines, transportation infrastructure, energy projects, other major industrial facilities, and sometimes even tourism facilities such as ski resorts. All development activities large and small have cumulative effects of some kind.

Some B.C. policy-makers are talking about the use of regional effects assessment (REA) and strategic effects assessments (SEA) to manage development-related effects at a broader level. CEA is usually part of a project-specific assessment. SEA normally targets the review of policies, plans, and programs while REA is a form of land-use planning, albeit targeted to an activity and region.

This article is a practitioner’s perspective on the generally accepted closest-to-project form of CEA and REA and their use in evaluating major projects under both the Canadian Environmental Assessment Act (1995, 2012) and some version of this under the yet-to-be-passed Bill C-69 Impact Assessment Act, along with British Columbia’s Environmental Assessment Act (1995, 2002, 2018). It provides a brief history of cumulative assessments in Canada and British Columbia, discusses methods for assessments, identifies challenges, and identifies a few specific issues aimed at improvement. We also offer some perspectives on regional impact assessment.


  • All development activities, large and small, have cumulative effects. With 7 billion people on the earth and still growing, there is enormous continuous strain on the natural environment, which supplies all the raw materials needed to meet all our needs and wants. In some cases, we can see the increased environmental pressures. In other cases, we perceive or have a mental impression of negative impacts, perhaps driven in part by a variety of interactive cognitive biases.
  • Cumulative effects assessment (CEA) has increased in importance over the past 20 years. It is now an accepted sub-discipline within project-specific environmental assessment processes and is gradually making its way into permitting/licensing regulatory decision-making for smaller projects and activities.
  • B.C. has some of the best CEA practitioners and they deploy a robust form of assessment compared to many other places.
  • CEA is conceptually simple but difficult to implement in practice. CEA is valuable for improving the environmental and social sustainability of a project and assisting government agencies with their project decision-making but there is an unrealistic expectation it will deliver definitive conclusions on the combined effects of past, present, and foreseeable human activities. CEA, and environmental assessment in general, is not the proper place for broader conversations about policy issues since many of these are far beyond the scope of any one project.
  • Given these limitations, regional effects assessment (REA) may be better for looking at the hypothetical futures of a place and building understanding about “what’s important”.
  • But REA is land use planning (LUP) and British Columbia’s experience with LUP is mixed. Perhaps a smaller scale more focused look at a place can help increase certainty and contain project development costs.
  • A must have pre-requisite for REA in B.C. is a clear understanding of how the results of such a process(es) will be integrated into regulatory decision-making. Both CEA and REA are tools. Neither are panaceas.