ABSTRACT
This chapter presents an historical and interdisciplinary overview of theories that seek to explain why people choose or are compelled to leave their places of residence and seek a new one. I contend that although a distinction can be made between voluntary and forced migration, it evolves along a continuum of individual and contextual situations. It is fruitful in that context to consider conjointly often disconnected corpuses of theories and to pave the way to re-embedding forced migration within migration theories in general. That issue is all the more pregnant in the case of migration linked to environmental hazards and climate change, because the impact of the environment on migration is often indirect and mediated first by economic factors which then makes migration more or less desirable, sometime compel population to move or, on the contrary, trap them in unsustainable surroundings.
