Human populations have put pressure on their natural surroundings throughout history. Yet the world is now facing truly global environmental challenges and rapid population growth in the final half of the twentieth century is a critical component to understanding these phenomena. In his article, Ambassador Richard Benedick examines a host of population dynamics and their complex interlinkages with three representative environmental issue areas: forests, freshwater resources, and climate change. These connections raise the importance of meeting the commitments made at the 1994 Cairo International Conference on Population and Development. Benedick maintains that investments in measures to slow the rate of population growth-and thereby to reach a stable population earlier, and at lower levels, than under current trends-would significantly reinforce efforts to address the environmental challenges of the century ahead, and considerably lower the cost of such efforts.