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Environ Manage. 2018 Jun;61(6):1062-1071. doi: 10.1007/s00267-018-1025-6. Epub 2018 Mar 19.

The Insignificance of Thresholds in Environmental Impact Assessment: An Illustrative Case Study in Canada.

Author information

1
Institute for Resources, Environment and Sustainability, University of British Columbia, 2202 Main Mall, Vancouver, BC, V6T 1Z4, Canada. cclarke@eos.ubc.ca.
2
WWF-Canada, 1588-409 Granville Street, Vancouver, BC, V6C 1T2, Canada. cclarke@eos.ubc.ca.
3
Fisheries and Oceans Canada, 9860 West Saanich Road, Sidney, BC, V8L 4B2, Canada. cclarke@eos.ubc.ca.
4
WWF-Canada, 1588-409 Granville Street, Vancouver, BC, V6C 1T2, Canada.
5
Forest Sciences Centre, University of British Columbia, 2424 Main Mall, Vancouver, BC, V6T 1Z4, Canada.
6
Institute for Resources, Environment and Sustainability, University of British Columbia, 2202 Main Mall, Vancouver, BC, V6T 1Z4, Canada.
7
Center for Ocean Solutions, 555E-99 Pacific Street, Monterey, CA, 93940, USA.

Abstract

Environmental assessment is the process that decision-makers rely on to predict, evaluate, and prevent biophysical, social, and economic impacts of potential project developments. The determination of significance in environmental assessment is central to environmental management in many nations. We reviewed ten recent environmental impact assessments from British Columbia, Canada and systematically reviewed and scored significance determination and the approaches used by assessors, the use of thresholds in significance determination, threshold exceedances, and the outcomes. Findings of significant impacts were exceedingly rare and practitioners used a combination of significance determination approaches, most commonly relying upon reasoned argumentation. Quantitative thresholds were rarely employed, with less than 10% of the valued components evaluated using thresholds. Even where quantitative thresholds for significance were exceeded, in every case practitioners used a variety of rationales to demote negative impacts to non-significance. These reasons include combinations of scale (temporal and spatial) of impacts, an already exceeded baseline, model uncertainty and/or substituting less stringent thresholds. Governments and agencies can better protect resources by requiring clear and defensible significance determinations, by making government-defined thresholds legally enforceable and accountable, and by requiring or encouraging significance determination through inclusive and collaborative approaches.

KEYWORDS:

Environmental assessment; Environmental impact assessment; Significance; Significance determination; Thresholds

PMID:
29556722
DOI:
10.1007/s00267-018-1025-6
[Indexed for MEDLINE]

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