Massive population displacements are now regularly forecasted as one of the most dramatic possible consequences of climate change. Recent empirical studies, such as the EACH-FOR project (www.each-for.eu), have shown that environmental factors were increasingly important drivers of migration movements, both forced and voluntary. The dominant perspective on the issue, however, is rooted in environmental determinism: migration is conceived as a threat to human security, the only choice left when all other adaptation strategies have failed. Environmental ‘refugees’ are depicted as the expiatory victims of climate change, subjects of a humanitarian catastrophe in the making. Empirical studies, however, reveal a different picture, where migration becomes an adaptation strategy for those who are affected by the impacts of climate change. Yet mobility often remains a luxury, unavailable for those who cannot afford to migrate. Hence the most vulnerable are often stuck in places heavily impacted by climate change, unable to seek higher grounds and a better life. Building on case-studies conducted in Central Asia and Asia-Pacific within the framework of the EACH-FOR project, this paper refutes the dominant deterministic perspective and adopts a constructivist approach. It shows how policy responses to climate change impacts affect people’s ability to migrate, and why these policy responses often matter more than the very impacts of climate change in their migration decision. Considering that migration can improve human security rather than hinder it, the paper makes the case for migration policies to be part of adaptation plans. In that regard, a key political challenge will be the restoration of the right to mobility for the most vulnerable, in order to enable their human security.