Human security and environmental security, often reinforcing, can be at odds. One instance arises when greenlining, the creation or expansion of relatively exclusionary protected areas, leads to the mass displacement of local communities and the creation of a new variant of ‘environmental refugees’. The present research employs several methods to estimate the magnitude of environmental refugees in Africa and suggests that they number in the millions. Country-specific case studies are offered to lend historical context to these estimates. Environmentally oriented land reform is proposed as a partial mitigation for the social side effects of greenlining, and is briefly described in African and other settings. Copyright © 2001 John Wiley & Sons, Ltd.