An environmental impact assessment (EIA) is a process used to identify, predict and evaluate the likely environmental and social impacts of a proposed development before major decisions are made. It helps decision-makers modify, approve or reject projects in support of sustainable resource management.
Level: HL only; Subtopic 7.1, Natural resources: uses and management.
How an EIA works
An EIA examines a proposed project, such as a dam, mine, road or power station, as part of a wider socio-ecological system. It considers how project inputs and activities may alter environmental storages, flows, ecosystem services and affected communities.
| Stage | Purpose |
|---|---|
| Screening and scoping | Determine whether an EIA is required and identify the significant impacts that need investigation. |
| Baseline study | Record existing ecological and social conditions against which future change can be assessed. |
| Impact prediction | Estimate direct, indirect, short-term, long-term and cumulative effects. |
| Mitigation planning | Propose ways to avoid, minimize, restore or compensate for damage. |
| Decision and monitoring | Approve, modify or reject the proposal, then check whether predicted impacts and mitigation measures are accurate. |
Making an EIA public allows local people to participate as stakeholders. This can promote environmental justice because communities affected by pollution, displacement or resource loss can contribute evidence and challenge decisions. However, EIA requirements and enforcement differ between countries, and economic or political interests may influence outcomes.
For example, assessments of Brazil's Belo Monte Dam considered electricity generation alongside forest loss, altered river systems and effects on Indigenous and river-dependent communities. Different technocentric, anthropocentric and ecocentric perspectives therefore produced different judgments about whether the project was acceptable.
A common misconception is that an EIA automatically prevents development. It does not: it provides evidence for decision-making, and its effectiveness depends on data quality, public participation, transparency, monitoring and enforcement.
Exam technique
For an explain question, link baseline evidence to predicted impacts and mitigation. For evaluate, balance the EIA's strengths against limitations, use a named development example, consider stakeholder perspectives, and reach a supported conclusion.
