Globally, there is a heightened concern and attention regarding the additive, antagonistic, and/or sometimes synergistic effect of multiple stressors on social-ecological systems. These “cumulative effects” represent some of the most complex and urgent environmental, social and governance issues of today, such as climate change, habitat and biodiversity loss, as well as the impacts of many development activities across some landscapes. While the practice of assessing cumulative impacts has expanded globally, often as an integral part of environmental impact assessments, there continues to be evidence of flawed practices, leading to inadequate assessments of combined past, present and future human activities, and natural processes.

In all of our domestic and international work relating to cumulative effects assessment over the last four decades, we’ve consistently taken a systematic and rigorous approach grounded in the principles and practices of adaptive environmental assessment and management (AEAM ). Our work in cumulative effects assessment can also take several slightly different forms including strategic environmental assessments, regional assessments, ecological risk assessments, ecosystem-based, and weight of evidence approaches. With these approaches we commonly identify the appropriate spatial scales and time horizons for assessing impacts, engage with diverse stakeholders to address issues and inequalities, collaboratively build conceptual or quantitative models of how activities might affect valued ecosystem components, predict the range of possible futures based on Western science and traditional or local knowledge, explicitly acknowledge and explore the uncertainty in those predictions, and design programs to monitor outcomes, test predictions and adjust management actions over time. Furthermore, we also seek to work across siloes by applying a systems perspective to integrate cumulative effects assessment with climate change adaptation to ensure resilient ecosystems and communities. The most recent reviews of current CEA best practice are consistent with the approach we’ve been using and evolving since 1979.

Our work in this practice area encompasses:

• regional and/or strategic assessments of cumulative impacts;
• ecological risk assessments and/or weight of evidence approaches;
• rigorous impact assessments and adaptive management plans for industries and government agencies;
• scientific advice and support in developing cumulative effects frameworks;
• third party review of impact assessments on behalf of First Nations and communities, and evaluations of compliance with international best standards.

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Explore the following sample of projects from ESSA’s Cumulative Effects Assessment Practice Area which showcase our work. You can also explore a foundational reading list from which we draw inspiration. Contact Carol Murray ([email protected]) or Marc Neltz ([email protected]) for more information about our work in this practice area.

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