Environmental Management

, Volume 61, Issue 6, pp 1062–1071 | Cite as

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

  • Cathryn Clarke MurrayEmail author
  • Janson Wong
  • Gerald G. Singh
  • Megan Mach
  • Jackie Lerner
  • Bernardo Ranieri
  • Guillaume Peterson St-Laurent
  • Alice Guimaraes
  • Kai M. A. Chan


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.


Environmental assessment Environmental impact assessment Significance Thresholds Significance determination 



The authors wish to thank Linda Nowlan and James Casey for useful discussions and two anonymous reviewers for their help improving the manuscript. This research was supported in part by the Gordon and Betty Moore Foundation through a grant to WWF-Canada [#2229.01] to support JW and CCM and an NSERC Discovery grant to KC. BDR was supported by a scholarship from the Science Without Borders Program, Coordenação de Aperfeiçoamento de Nível Pessoa, Brazil (CAPES). The funders had no role in the design of the study. Statement of responsibilities: GS, CCM, JL, MM, BR and GP designed the global project; JW and CCM designed the BC case study; AG, BR, CCM, GP, GS, GY, JL, JW, and MM collected data; GS, CCM and JW analysed data; CCM and JW led and all authors contributed to writing and editing the manuscript.

Compliance with ethical standards

Conflict of interest

The authors declare that they have no conflict of interest.


  1. Antoniuk T, Kennett S, Aumann C, Weber M, Davis Schuetz S, McManus R, McKinnon K, Manuel K (2009) Valued component thresholds (management objectives) project. Calgary, AB, p 164Google Scholar
  2. Ball MA, Noble BF, Dubé MG (2013a) Valued ecosystem components for watershed cumulative effects: an analysis of environmental impact assessments in the South Saskatchewan River watershed, Canada. Integr Environ Assess Manage 9(3):469–479CrossRefGoogle Scholar
  3. Ball M, Somers G, Wilson JE, Tanna R, Chung C, Duro DC, Seitz N (2013b) Scale, assessment components, and reference conditions: issues for cumulative effects assessment in Canadian watersheds. Integr Environ Assess Manage 9(3):370–379CrossRefGoogle Scholar
  4. BC EAO – British Columbia Environmental Assessment Office (2013). Guideline for the selection of valued components and assessment of potential effects. Prepared by the BC Environmental Assessment Office. Updated online 09-09-2013
  5. Booth AL, Skelton NW (2011) “You spoil everything!” Indigenous peoples and consequences of industrial development in British Columbia. Environ Dev Sustain 13:685–702CrossRefGoogle Scholar
  6. Bowen GA (2009) Document analysis as a qualitative research method. Qual Res J 9(2):27–40CrossRefGoogle Scholar
  7. Brazil MMA/CONAMA - Ministry of the Environment (MMA) and National Environment Council (CONAMA) (2012). CONAMA Resolutions. Resolution 1996.
  8. Briggs S, Hudson MD (2013) Determination of significance in Ecological Impact Assessment: past change, current practice and future improvements. Environ Impact Assess Rev 38(0):16–25CrossRefGoogle Scholar
  9. Canadian Council of Ministers of the Environment (CCME) (1999) Canadian national ambient air quality objectives: process and status. Canadian environmental quality guidelines, 1999, Canadian Council of Ministers of the Environment, Winnipeg, p 8Google Scholar
  10. Canadian Environmental Assessment Act (2012) SC 2012, c 19, s 52Google Scholar
  11. Canter LW (1996) Environmental impact assessment (No. 2). McGraw-Hill IncGoogle Scholar
  12. Cashmore M (2004) The role of science in environmental impact assessment: process and procedure versus purpose in the development of theory. Environ Impact Assess Rev 31;24(4):403–426CrossRefGoogle Scholar
  13. Christensen L, Krogman N (2012) Social thresholds and their translation into social-ecological management practices. Ecol Soc 17(1):5CrossRefGoogle Scholar
  14. CEAA – Canadian Environmental Assessment Agency (2010) A reference guide for the Canadian Environmental Assessment Ace: determining whether a project is likely to cause significant adverse environmental effects. Prepared by the Federal Environmental Assessment Review Office. Updated online 10-10-2012
  15. CEAA – Canadian Environmental Assessment Agency (2015) Operational policy statement: determining whether a project is likely to cause significant adverse environmental effects under the Canadian Environmental Assessment Act, 2012.
  16. CEPA - Canadian Environmental Protection Act (1999) List of toxic substances managed under CEPA (Schedule 1). Updated 15 June, 2016. Accessed 22 June, 2016Google Scholar
  17. Council on Environmental Quality (2007) A Citizen’s Guide to the NEPA—having your voice heard.
  18. Dubé MG (2003) Cumulative effect assessment in Canada: a regional framework for aquatic ecosystems. Environ Impact Assess Rev 23(6):723–745CrossRefGoogle Scholar
  19. Duinker PN, Beanlands GE (1986) The significance of environmental impacts: an exploration of the concept. Environ Manage 10(1):1–10CrossRefGoogle Scholar
  20. Duinker PN, Burbidge EL, Boardley SR, Greig LA (2012) Scientific dimensions of cumulative effects assessment: toward improvements in guidance for practice. Environ Rev 21(1): 40–52Google Scholar
  21. Ehrlich A, Ross W (2015) The significance spectrum and EIA significance determinations. Impact Assess Proj Apprais 33(2):87–97CrossRefGoogle Scholar
  22. Enbridge Northern Gateway Pipeline (ENGP) (2010) Environmental Impact Assessment Report. Volume 6AGoogle Scholar
  23. Environmental Assessment Act, S.B.C. (2002) c.43, ss.11, 21Google Scholar
  24. Environment Canada (2011) Scientific Assessment to Inform the Identification of Critical Habitat for Woodland Caribou (Rangifer tarandus caribou), Boreal Population, in Canada: 2011 update. Ottawa, ON, p 102Google Scholar
  25. Gibson R, Hassan S, Holtz S, Tansey J, Whitelaw G (2005) Sustainability assessment criteria, processes and applications. Earthscan, LondonGoogle Scholar
  26. Groffman PM, Baron JS, Blett T, Gold AJ, Goodman I, Gunderson LH, Levinson BM, Palmer MA, Paerl HW, Peterson GD, Poff NL (2006) Ecological thresholds: the key to successful environmental management or an important concept with no practical application? Ecosystems 9(1):1–3CrossRefGoogle Scholar
  27. Hicks T (2011) Exploring the use of arguments in impact assessment: a case study for impact significance arguments. Master of Arts, Royal Roads University, p 111Google Scholar
  28. International Finance Corporation (IFC) World Bank Group (2013) Good practice handbook. Cumulative impact assessment and management: Guidance for the Private Sector in Emerging Markets. IFC, Online Publication, p 102Google Scholar
  29. Johnson CJ (2013) Identifying ecological thresholds for regulating human activity: effective conservation or wishful thinking? Biol Conserv 168:57–56CrossRefGoogle Scholar
  30. Jones M, Morrison-Saunders A (2016) Making sense of significance in environmental impact assessment. Impact Assess Proj Apprais 34(1):87–93CrossRefGoogle Scholar
  31. Joseph C, Zeeg T, Angus D, Usborne A, Mutrie E (2017) Use of significance thresholds to integrate cumulative effects into project-level socio-economic impact assessment in Canada. Environ Impact Assess Rev 67:1–9CrossRefGoogle Scholar
  32. Kennett S (2006) From science-based thresholds to regulatory limits: implementation issues for cumulative effects management. Environ Can 23: 2009Google Scholar
  33. Killingsworth MJ, Palmer JS (1992) The environmental impact statement and the rhetoric of democracy. In Ecospeak: Rhetoric and Environmental Politics in America, Southern Illinois University Press, Carbondale, IL, pp 163–192Google Scholar
  34. Krippendorff K (2004) Content analysis: an introduction to its methodology. Sage. Thousand Oaks, CAGoogle Scholar
  35. Lawrence D (2005) Significance criteria and determination in sustainability-based environmental impact assessment. Canadian Environmental Assessment Agency, Ottawa, ON. Google Scholar
  36. Lawrence D (2007) Impact significance determination—back to basics. Environ Impact Assess Rev 27:755–769CrossRefGoogle Scholar
  37. McGuigan EK (2015) Social impact assessment in rural and small-town British Columbia. Doctoral dissertation, University of British Columbia, p 200Google Scholar
  38. Moore JW, Carr-Harris C, Gottesfeld AS, MacIntyre D, Radies D, Cleveland M, Barnes C, Joseph W, Williams G, Gordon J, Shepert B (2015) Selling first Nations down the river. Science 349(6248):596–596CrossRefGoogle Scholar
  39. Morgan RK (1998) Environmental impact assessment. Kluwer, DordrechtGoogle Scholar
  40. NEPA (National Environment and Planning Agency, USA) (2007). Guidelines for conducting environmental impacts assessmentGoogle Scholar
  41. Noble B, Liu J, Hackett P (2017) The contribution of project environmental assessment to assessing and managing cumulative effects: individually and collectively insignificant? Environ Manage 59(4):531–545CrossRefGoogle Scholar
  42. Sadler B (1996) International study of the effectiveness of environmental assessment final report—environmental assessment in a changing world: evaluating practice to improve performance. Minister of Supply and Services Canada, OttawaGoogle Scholar
  43. Sadler B, Fuller K, Ridgway B, McCabe M, Bailey J, Saunders R (2002) Environmental impact assessment training resource manual, 2nd ed. United Nations Environment Programme, GenevaGoogle Scholar
  44. Sevier OH, Hatfield TF (2001) The determination of thresholds of environmental significance in the application of the California Environmental Quality Act (CEQA). Faculty Fellows Program, Center for California Studies, California State University, SacramentoGoogle Scholar
  45. Thompson MA (1990) Determining impact significance in EIA: a review of 24 methodologies. J Environ Manage 30(3):235–250CrossRefGoogle Scholar
  46. Teck Coal Limited (2011) Line Creek operations phase II project. Environmental Assessment Certificate Application. Volume B2Google Scholar
  47. Udofia A, Noble B, Poelzer G (2017) Meaningful and efficient? Enduring challenges to aboriginal participation in environmental assessment. Environ Impact Assess Rev 65:164–174CrossRefGoogle Scholar
  48. Wang Y, Morgan RK, Cashmore M (2003) Environmental impact assessment of projects in the People’s Republic of China: new law, old problems. Environ Impact Assess Rev 23(5):543–579CrossRefGoogle Scholar
  49. Welsh Office (1999) Environmental Impact Assessment (EIA), Annex B. Welsh Office. Circular 11/99Google Scholar
  50. Weston J (2000) EIA, decision-making theory and screening and scoping in UK practice. J Environ Assess Policy Manage 43(2):185–203Google Scholar
  51. Wood C (2003) Environmental impact assessment: a comparative review. Pearson Education, New York, NY, p 430Google Scholar
  52. Wood C, Jones C (1997) The effect of environmental assessment on UK local planning authority decisions. Urban Stud 34:1237–1257CrossRefGoogle Scholar
  53. Wood G (2008) Thresholds and criteria for evaluating and communicating impact significance in environmental statements: ‘See no evil, hear no evil, speak no evil’? Environ Impact Assess Rev 28(1):22–38CrossRefGoogle Scholar
  54. Wood G, Rodriguez-Bachiller A, Becker J (2007) Fuzzy sets and simulated environmental change: evaluating and communicating impact significance in environmental impact assessment. Environ Plan A 39(4):810–829CrossRefGoogle Scholar

Copyright information

© Springer Science+Business Media, LLC, part of Springer Nature 2018

Authors and Affiliations

  • Cathryn Clarke Murray
    • 1
    • 2
    • 5
    Email author
  • Janson Wong
    • 2
    • 3
  • Gerald G. Singh
    • 1
  • Megan Mach
    • 4
  • Jackie Lerner
    • 1
  • Bernardo Ranieri
    • 1
  • Guillaume Peterson St-Laurent
    • 1
  • Alice Guimaraes
    • 1
  • Kai M. A. Chan
    • 1
  1. 1.Institute for Resources, Environment and SustainabilityUniversity of British ColumbiaVancouverCanada
  2. 2.WWF-CanadaVancouverCanada
  3. 3.Forest Sciences CentreUniversity of British ColumbiaVancouverCanada
  4. 4.Center for Ocean SolutionsMontereyUSA
  5. 5.Fisheries and Oceans CanadaSidneyCanada

Personalised recommendations