According to recent scientific data, the quantified targets of the Climate Change Convention and the Kyoto Protocol to reduce emissions of greenhouse gases will not be sufficient to prevent anthropogenic dangerous interference with the climate system. It is not likely that the new targets that are currently being negotiated will prevent this either. It will therefore be necessary for countries to adapt to climate change, including a sea level rise. Unlike developed countries, such as the Netherlands, many developing countries do not have the technological, economic and administrative capacities to prepare their infrastructure and societies in time for the inevitable injurious consequences of climate change. Low-lying island states, such as the Maldives and Tuvalu, and low-lying coastal areas, such as some areas in Alaska and along the Gulf of Bengal, will (partially)disappear under sea level. This may result in mass migration of people and even peoples during this century. However, these climate change-displaced persons do not have access to other countries and lack adequate international judicial protection. The improvement of their situation is urgent. This booklet contains the inaugural lecture given by the author on accepting the Chair of Professor of International Environmental Law at the Faculty of Law of the University of Amsterdam (UvA) on 4 December 2008.