In 2010, the United Nations Population Fund (UNFPA), the International Institute for Environment and Development (IIED) and El Colegio de Mexico hosted an expert group meeting in Mexico to discuss aspects of population dynamics with particular focus on adaptation to climate change. Synthesising the emergent themes from this meeting, the groups collaborated to produce this publication, which seeks to plug a knowledge gap in the adaptation field with regard to how population dynamics impacts adaptation planning. The authors argue that too much of adaptation effort is spent on reacting to events and that we must transition to an anticipatory model which adapts to how things will be rather than how things are now. Population dynamics is a crucial aspect of this, playing a central role in livelihoods, location, economic and environmental vulnerability and resilience, as well as helping to avoid static perceptions of vulnerability. The publication is divided into three sections. Section one concerns the key concepts of population dynamics and adaptation. It discusses incorporating population dynamics in climate change adaptation policy and practice, tapping synergies and avoiding exclusionary policies with regard to urbanisation, and on migration as a response to local and global transformations. On this last topic, the author proposes a typology of mobility, accounting for the interrelations between climate change and socioeconomic and cultural transformations and highlighting the diversity of migration and its drivers. The second section discusses the sources and methodologies of population data for adaptation, mapping a path to incorporating such data into adaptation analysis and programming. Finally, the third section covers the planning and practice of adaptation. Firstly, a case study is presented on the local vulnerability and adaptive capacity in five urban areas of Malawi; mapped census data shows high variation in adaptive capacities of households and communities, with comparable vulnerabilities to rural communities. The final two chapters consider the challenges of adaptation in an early but unassisted urban transition, and planning for adaptation in a megacity (using the Mexico City metropolitan area as a case study).