The sixth Global Environment Outlook (GEO-6) Regional Assessment for North America paints a comprehensive picture of the environmental factors contributing to human health and well-being at the regional level. Backed by a large body of recent,credible scientific evidence, regional-wide consultations and a robust intergovernmental process, the assessment demonstrates that regional and global multilateral environmental agreements have improved environmental conditions in North America. For many, the idea of North America evokes an image of open spaces, endless forests, mighty rivers and prairies stretching to the horizon. In the past century, major cities with towering skyscrapers at their core, surrounded by a suburban ring and an outer peri-urban zone, are included in the vision. Canada and the US have converted landscapes, built infrastructure, and consumed energy on a vast scale. Over four centuries, forests, grasslands, and wetlands have been cleared for agriculture. In the 20th century, some previously farmed land has reverted to forests while others have become peri-urban, suburban, and urban areas.