Environmental Science Environmental Assessment
Bram Noble
  • LAST REVIEWED: 03 December 2019
  • LAST MODIFIED: 22 February 2018
  • DOI: 10.1093/obo/9780199363445-0092


Environmental assessment (EA) is the process of identifying the future consequences of a current or proposed action on the environment, and identifying ways to manage potentially adverse consequences while creating or enhancing positive ones, such that informed decisions can be made about the acceptability of an action. EA originated from the US National Environmental Policy Act (NEPA) of 1969, which became law in 1970. NEPA was the first legislation to require that those proposing to undertake certain developments had to demonstrate that the action would not adversely affect the environment. Although most EAs are completed for individual projects, such as mines, energy pipelines, or major highways, in some jurisdictions EA is also applied to land use plans, entire resource sectors, and even national policies. Most nations require an EA for major projects proposed by government agencies, or for projects proposed by private developers that require government approvals such as permitting or licensing. Some form of EA is required by law in more than 190 countries globally. In Canada, for example, EA requirements for major projects are legislated federally under the Canadian Environmental Assessment Act 2012, and under the laws of each of Canada’s provinces and territories. In Europe, the European Union EIA Directive 2011/92/EU sets out the provisions for EA, with member nations also having their own laws and regulations that address more country-specific development matters. The EA process varies by jurisdiction, but there is some general consistency in the types of issues that are addressed. Typically, an EA includes an analysis of baseline biophysical (e.g., water quality, air quality, wildlife, vegetation) and social conditions (e.g., population, health, values, land uses) in the region in which the undertaking is proposed; predictions of the potential impacts of the undertaking on components of the biophysical and social environment; the identification of ways to mitigate potential adverse impacts and enhance positive ones; and an analysis of whether the impacts that remain after mitigation are likely to be significant based on regulatory standards, ecological limits, or social acceptability. This information is often compiled by independent consultants or, in some cases, the government agency responsible for the project. An opportunity for public review or comment exists in most jurisdictions. This information is then taken into consideration by decision makers, usually state, regional, or municipal governments, and a decision is made on whether to approve the proposed undertaking, reject it, or approve it subject to certain conditions being met. In most cases, a follow-up plan that includes monitoring and reporting is also implemented as part of the EA process, to ensure that mitigation is working and to identify any unforeseen impacts.

General Overviews

There is a variety of resources that provide a general overview of, and introduction to, the EA process. Partidario 2012 provides a quick-reference tip-sheet on EA, prepared for the International Association for Impact Assessment as part of the organization’s Fast Tips series. There are several textbooks that explain the EA process and provide procedural guidance on the practice of EA in different jurisdictions. Noble 2015, for example, introduces the EA process and provides a guide for practice in the Canadian context; Elliot 2014 introduces the regulatory EA process in Australia, focused on contemporary issues in EA practice. Eccleston 2011 focuses on best professional practice, specifically for preparing different types of assessment including risk assessments and assessments of greenhouse gas emissions, while Perdicoulis, et al. 2012 provides guidance on how to connect EA systems with other forms of environmental management and monitoring systems. Page 2006 provides practical guidance on how to write a convincing EA report and the basic requirements of what should be included and how assessment information is best communicated. For more critical assessments of EA, Morgan 2012 and Lawrence 2013 reflect on the state of the discipline and the practice, discussing how the field has evolved and the enduring and emerging challenges to EA. Bond 2017 provides direction on the research needed to address these enduring challenges to EA and help achieve broader sustainability objectives. Sustainable development is the focus of Morrison-Saunders, et al. 2015—this edited volume provides rich insight to sustainability assessment methods and approaches to advance EA beyond mitigating adverse impacts and instead promote overall positive outcomes.

  • Bond, Alan. 2017. What is the role of impact assessment in the long term? Journal of Environmental Assessment Policy and Management 17.1.

    DOI: 10.1142/S1464333215500064

    A reflection on the current state and future role of EA from a sustainability perspective. The author argues that sustainable development is often the stated goal of EA, but EA doesn’t always deliver sustainable outcomes. A case is made for EA research focused on inter-generational impacts.

  • Eccleston, Charles. 2011. Environmental impact assessment: A guide to best professional practices. Boca Raton, FL: CRC.

    DOI: 10.1201/b10717

    An overview of how to prepare different types of impact assessments, including cumulative impact assessments, greenhouse gas emissions assessments, risk assessments, and social impact assessments. The book is written for a practitioner audience with emphasis on best professional practices.

  • Elliot, Mandy. 2014. Environmental impact assessment in Australia: Theory and practice. 6th ed. Sydney: Federation Press.

    An overview of systems, practices, and contemporary issues in EA in the Australian context. This book is valuable to the practitioner, especially those new to the EA process and interested in understanding EA principles and technical procedures for determining and presenting impacts.

  • Lawrence, David. 2013. Impact assessment: Practical solutions to recurrent problems and contemporary challenges. 2d ed. Hoboken, NJ: Wiley.

    DOI: 10.1002/9781118678381

    Starting with a review of conventional approaches to impact assessment, the book then proceeds to examine contemporary challenges to impact assessment and provides potential solutions to address them. This book is a valuable reference for practitioners, and is global in perspective.

  • Morgan, Richard. 2012. Environmental impact assessment: The state of the art. Impact Assessment and Project Appraisal 30.1: 5–14.

    DOI: 10.1080/14615517.2012.661557

    This is an important paper for anyone interested in current state-of-the-art of EA and how the field has evolved. Morgan succinctly explains the 40-year evolution of EA, identifying major developments and enduring challenges. He then challenges the reader, asking whether EA is ready for the future. This paper is highly recommended as required reading for any graduate level EA course.

  • Morrison-Saunders, Angus, Jenny Pope, and Alan Bond, eds. 2015. Handbook of sustainability assessment. Cheltenham, UK: Edward Elgar.

    This book is a departure from traditional, project-focused EA. Emphasis is placed on sustainability assessment and how to direct impact assessment and decision-making, including EA, toward sustainability. An edited volume, the contributions address a range of topics that concern both the theory and practice of decision-making toward sustainability, including regional EA, energy futures, urban systems, multi-criteria analysis, and public participation to name a few. The book is useful for academics and graduate-level teaching.

  • Noble, Bram F. 2015. Introduction to environmental impact assessment: A guide to principles and practice. 3d ed. Don Mills, ON: Oxford Univ. Press.

    An introductory text to the principles and practice of environmental assessment. In addition to project-based EA, the book also explores regional cumulative effects assessment, strategic environmental assessment, and professional practice and ethics. The book is a useful textbook for teaching introductory EA, and a reference manual for EA practitioners.

  • Page, John. 2006. Make it easy on your readers: Ideas on environmental impact document focus, organization and style. Impact Assessment and Project Appraisal 24.3: 235–245.

    DOI: 10.3152/147154606781765165

    This is one of the few articles that provides practical guidance on how to write a convincing EA report. The article clearly lays out what needs to be said in an EA report, where it should be said, and how it should be said. This is a valuable resource for EA practitioners and for those who wish to learn about the basic structure of an environmental impact statement (EIS).

  • Partidario, Maria. 2012. Impact assessment. Fast Tips 1. Fargo, ND: International Association for Impact Assessment.

    This two-page document is one of several in the Fast Tips series published by the International Association for Impact Assessment. The Fast Tips on impact assessment succinctly lays out the technical and procedural nature of impact assessment, followed by a list of five important things to know about impact assessment and five important things to do. This is a valuable quick-reference document for those new to impact assessment. Teachers of impact assessment may find it valuable as a first introduction to the subject for their students.

  • Perdicoulis, Anastassios, Bridget Durning, and Lisa Palframan, eds. 2012. Furthering environmental impact assessment: Towards a seamless connection between EIA and EMS. Northampton, MA: Edward Elgar.

    This edited volume extends beyond the basics of EA and focuses on how to approach EA to ensure that impacts are managed as promised. Several cases and applications are presented, including sector-specific examples that focus on the management of development. The book is valuable for those seeking specific examples of how to manage risk during the design and development of EA for major projects.

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