Introduction

The development of EIA commitments in international law has occurred against a backdrop of normative arrangements existing in domestic and international legal settings. EIA as a distinct form of public decision-making was first developed under US federal law as part of the National Environmental Policy Act (NEPA). Subsequently, EIA processes were developed by a number of US states, and in the mid-1970s countries such as Canada, France, Australia and New Zealand developed their own EIA processes. Since the 1970s, the adoption of EIA legislation has grown steadily throughout the world, and it is now estimated that over 100 countries have EIA legislation. EIA norms have not only spread horizontally to other states, but they have also spread vertically, influencing the development of EIA norms in international law and within international organizations. The globalization of EIA commitments has not, however, been a one-way projection of domestic environmental policy into a transnational setting. The reception and development of EIA commitments by other states in both their domestic and international decision-making processes has also been influenced by general principles of international environmental law, such as the principle of nondiscrimination, the duty to prevent transboundary harm and the duty to cooperate with other states to preserve and protect the natural environment. Latterly, the constellation of principles surrounding sustainable development that has become embedded in transnational environmental governance structures has also influenced the development of EIA processes in transnational legal settings.