Environmental factors play a growing role in population movements

The volume of displaced people may increase as environmental changes, particularly those induced by global warming, disrupt livelihoods dependent on the stability of local ecosystems. As shown in Figure 1.4, natural disasters have a significant impact on migration flows: not only because livelihoods are destroyed by earthquakes, floods and droughts, but also because natural disasters affect the entire economic activity. The famine in the Horn of Africa is a good illustration of this phenomenon. In 2010, more than 2 million people hit by natural disasters benefited from UN High Commissioner for Refugees (UNHCR) interventions (UNHCR, 2011b).

Figure 1.4. Migration flows after natural disasters

Thousands of migrants

Notes: Natural disasters in year t: drought in Ethiopia, tsunami in Indonesia, cyclone in Myanmar, storm in Nicaragua, flood in Mozambique, and earthquakes in other countries (*).

Source: Authors' calculations based on the Database on Immigration in OECD countries (DIOC), OECD.

In the long run, estimates on the number of migrants generated by climate change (between 200 million and 1 billion by 2050) are questionable, mainly because they do not consider the capacity of populations to adapt to new conditions, and, above all, gradual environmental changes (UNDP, 2009). The number of migrants will in particular depend on how public policy responds to the environmental challenge. In any case, low-income countries are likely to be more exposed to the consequences of climate change, both because of the higher degree of vulnerability of the poorest populations, and because of the lower responsiveness of public authority.

Although international law does not acknowledge the legal status of "eco-refugees" (Martin, 2010), the community should be prepared to face more internal and international displacements induced by environmental disasters.