This is what the International Organization for Migration has to say….
People have always moved because of their environment. They have run to survive in the wake of natural disasters, as in the case of Typhoon Haiyan in the Philippines, or Hurricanes Katrina and Sandy in the US. Or, they decide to migrate away from harsh environments to seek better opportunities for life and livelihood. Climate accelerates environmental degradation and can lead to increased intensity and frequency of hydro- meteorological (water-driven) disasters. For this very reason, it is already influencing environmental migration around the world. Forecasts of the number of people having to move due to climate change and environmental degradation by the year 2050 vary somewhere between 25 million and I billion – depending on which climate scenarios ultimately materialize. While the exact magnitude may be somewhat uncertain, the actual impact on people is not. All of the world’s regions and nations will experience some of impact of this transformational challenge.
Consider the case of Africa. African states are likely to be most vulnerable to multiple stresses, with up to 250 million people projected to suffer from water and food insecurity, and, in low-lying areas, rising sea levels. While only 1% of Africa’s land is located in these low-lying areas, this land supports 12% of its urban population. A majority of Africa’s people live in lower altitudes – areas like the Sahel, which is just south of the Sahara. It is here that worst effects of water scarcity, hotter temperatures and longer dry seasons will occur. Climate change is expected to aggravate many existing migratory pressures around the world, increasing the number of sudden humanitarian crises and disasters in areas least able to cope, such as those parts of our world already mired in poverty or prone to conflict.
Furthermore, there is growing evidence of the links between climate change, migration and conflict. Climate change will increasingly threaten our collective security in many parts of the world, disproportionately affecting the least developed countries. Environmental degradation and the movement of peoples from rural areas to already overcrowded cities will be a formidable development challenge as we move into the future.
(Sources: International Organization for Migration; “ Climate Change, Migration and Conflict,” Center for American Progress )