Environmental impact statement is a report that evaluates the likely environmental effects of a planned government project or program. A number of countries have laws requiring environmental impact statements.
The purpose of an environmental impact statement is to ensure that a government agency considers the environmental damage that may result from a project over which it has authority. The agency must identify ways of reducing harm and consider alternatives to the project that may be less damaging. Normally, other interested parties—such as state and local agencies, businesses, or individuals—can comment on the project during the environmental impact review process. After a final report is issued, the agency itself decides whether to go ahead with the project or whether to alter or abandon it.
The world’s first law requiring environmental impact statements was the National Environmental Policy Act, a United States law that went into effect in 1970. Under the law, any U.S. agency that plans to build a dam, power plant, or other facility must issue an environmental impact statement. A federal agency also must issue a statement for any large state, local, or private project that it will fund or regulate. Several states have similar laws for projects by state agencies or local governments.
In 1992, the United Nations Conference on Environment and Development—also known as the Earth Summit—was held in Rio de Janeiro, Brazil. As a result of the summit, more than 170 countries approved Agenda 21, a plan to achieve worldwide economic development in an environmentally responsible way. Since then, several countries have begun to require environmental impact statements. In most cases, the process for preparing the statements is similar to the U.S. approach.