The world is familiar with refugee movements caused by war, famine, and natural disasters. It is overwhelmingly the poorer third world states that do not close their borders and accept millions of refugees, some of whom remain for years. Today, among developed countries, the United States, Sweden, and Finland offer temporary shelter to victims of natural disasters, and Denmark accepted some Afghan drought victims from 2001 to 2006. Global warming, however, is already on the point of creating a new category — the climate refugee. According to the United Nations Framework Convention on Climate Change (UNFCCC), current mitigation efforts could result in a global average temperature rise of 3 degrees Celsius rather than 2 degrees. In that event, the Economic Review of Climate Change (the Stern Review) suggests, 550 million more people would be at risk of hunger, and 170 million more would suffer severe coastal floods. Crop yields would fall sharply, and there would be more droughts interspersed with more severe flooding. The Intergovernmental Panel on Climate Change (IPCC) says that climate change may displace 150 million people by 2050; the Stern Review puts the figure at 200 million.
Larger climate changes pose potentially gigantic refugee problems. To start with, it is harder to identify the victims of slower processes than those of sudden natural disasters. Secondly, the victims of wider climate change fall through the net of definitions in international law. The current U.N. treaty, the Convention and Protocol Relating to the Status of Refugees, dates from 1951, and applies only to those who fear or flee persecution. As for internal displacement, the current U.N. document, Guiding Principles on Internal Displacement, dates from 1998 and is not legally binding, though it seems to cover most of those who flee natural disasters but do not cross national borders. The problem with more severe climate change is that those who cross national borders will not be covered by any U.N. instrument, as they will not satisfy the 1951 definition of refugees. A senior U.N. official says that reopening the 1951 convention would be legally risky because the original negotiations that brought it into being were very difficult, and it may be no easier to reach an agreement now. The difficulty of reaching, let alone enforcing, any agreement will be compounded by the fact that it is the poorest in the poorest countries who will suffer most and in the greatest numbers.