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.