LAUSR

The third decade of the 21st century will be one of milestones and turning points for impact assessment (IA). The United States’ globally influential National Environmental Policy Act (NEPA), which enshrined environmental assessment (EA) into law, is 50 (see e.g. Caldwell 1988). Meanwhile, the United Nation’s much younger Sustainable Development Goals (SDGs) have an agenda to 2030 and the International Panel on Climate Change’s 2050 carbon neutral targets are drawing closer, while the 1.5°C and 2°C Paris Agreement targets looking frighteningly unlikely to be met (UNEP, 2019). In this context, impact assessments of all types will play an important role in delivering the evidence necessary to support climate change mitigation, promote environmental justice and advance a sustainable future. This Special Issue of Impact Assessment and Project Appraisal takes a timely opportunity to consider the shape and role of impact assessment (IA) for at least the next half-century. The Special Issue’s theme, ‘IA for the 21st century—What future?’ aims to push our thinking about IA’s prospects and potential. We asked for bold and visionary contributions that would stretch our ideas beyond existing practice and policy to envision the major opportunities, challenges, changes and paradigm shifts that are likely to shape IA. Questions our contributors grappled with included: What does the future of impact assessment look like?