How to Assess the Significance of Environmental Impacts

Abstract

In the context of the Environmental Impact Studies, the determination of the significance of the impacts is a fragile aspect that has been the subject of discussion and criticism in the international scientific community. There are no objective criteria for such determination, resulting in very subjective evaluations, generally determined by the analysts' experience and influenced by their professional profile. The commonly employed methods are derived from normative valuations using certain rating scales, which are used in the same way for quite different ecological, economic and social processes. Then, once a ranking of impacts significance values is established, the subjectivity of the process is hidden under a seemingly objective number. The proposed method establishes a simple routine of integrated analysis considering a set of characteristics of environmental impacts, including persistence, reversibility spatial amplitude, synergy magnitude, and cumulative effects. Although this method does not eliminate the subjectivity of the process, it makes explicit the criteria used for assessing the significance of impacts providing greater transparency to the process, contributing to a broader understanding of the profile of the impacts of the project.

Attributing significance to social impacts

“…Sometimes, the scales increase exponentially and sometimes not; this is a professional decision. Tagliani and Walter (2018) discussed how an assessor's experience and professional profile influence this process, even though once the values are assigned, the subjectivity of the process becomes hidden behind a seemingly objective number. The presentation of a number in the quantitative approach seems less clear than a category (such as moderate significance) in the qualitative approach because there is no standard numbering scale or common scoring totals used by practitioners.…”

“…If EIA is used to determine whether the consequences of projects are environmentally acceptable (Ehrlich & Ross, 2015), then SIA is used to determine whether the consequences are socially acceptable, not just for the project promoters but also for the local stakeholders and those who will be most impacted. Tagliani and Walter (2018) discussed how acceptance of the project can differ between locations (for instance local versus national versus international), and between times (a project that induces seasonal influx may be perceived differently at certain times of the year). Public consultations are events that confirm whether local stakeholders agree with the SIA findings, including the identification, significance attribution, and management measures of social impacts at a specific point in time.…”

Handbook of Social Impact Assessment and Management

“…Sometimes, the scales increase exponentially and sometimes not; this is a professional decision. Tagliani and Walter (2018) discussed how an assessor's experience and professional profile influence this process, even though once the values are assigned, the subjectivity of the process becomes hidden behind a seemingly objective number. The presentation of a number in the quantitative approach seems less clear than a category (such as moderate significance) in the qualitative approach because there is no standard numbering scale or common scoring totals used by practitioners.…”

“…If EIA is used to determine whether the consequences of projects are environmentally acceptable (Ehrlich & Ross, 2015), then SIA is used to determine whether the consequences are socially acceptable, not just for the project promoters but also for the local stakeholders and those who will be most impacted. Tagliani and Walter (2018) discussed how acceptance of the project can differ between locations (for instance local versus national versus international), and between times (a project that induces seasonal influx may be perceived differently at certain times of the year). Public consultations are events that confirm whether local stakeholders agree with the SIA findings, including the identification, significance attribution, and management measures of social impacts at a specific point in time.…”

Brazilian Environmental-Impact Assessment System: A Critical Analysis

“…With the collective experience accumulated along 50 years of application of this management instrument, several authors have presented contributions, criticisms and recommendations for the improvement of EIA, such as Beanlands and Duinker [4], Canter and Canty [5], Erickson [6], Sadler [7], Lawrence [8], Pölönen et al [9], Prenzel and Vanclay [10], Loomis and Dziedzi [11], Tagliani and Walter [12] and many others.…”