Introduction

Sea levels are presently rising by approximately three millimeters per year as a result of anthropogenic climate change, with the thermal expansion of ocean water and melting of Greenland and Antarctic ice being key contributors. A few millimeters may not sound like much, but over the course of this century the cumulative effects will present significant challenges for populations living in low-lying coastal plains, deltas, and on small island states. In recent years the popular media has identified communities in Alaska, Papua New Guinea, and Vanuatu as the first climate change refugees, by virtue of having to relocate because of coastal erosion and encroachment of the sea. In the scholarly community there has been a recent surge in the number of publications on the question of what to do – legally and practically – about people displaced by rising sea levels. Such questions are difficult to answer for a number of reasons, not the least being that we have few direct precedents to draw on. A particularly difficult problem will be what to do if entire sovereign states become uninhabitable as a result of mean sea level rise.

In suggesting answers to these and other related questions, this chapter:

• Reviews the physical processes that affect the relative locations of coastal settlements and the sea, and identifies current and projected rates of change

• Describes the impacts of sea level change on coastal settlements

• Provides rough estimates of the number of people exposed

• Identifies options in adaptation, including migration

• Explains the challenges faced in dealing with people who may become internally displaced within their own countries by rising sea levels

• Considers the situation of citizens of states that may cease to be habitable

• Analyzes international legal arrangements that may be somewhat applicable to the protection of displacees

• Suggests pathways for action by a concerned international community