In Bangladesh, about 12 million to 17 million people have fled their homes in recent decades because of environmental disasters -- and the low-lying country is likely to experience more intense flooding in the future. In several countries in Africa's Sahel region, bordering the Sahara, about 10 million people have been driven to move by droughts and famines.
In the Philippines, upwards of 4 million people have moved from lowlands to highlands as a result of deforestation. And in an earlier era, about 2.5 million Americans became ecomigrants after droughts and land degradation during the Dust Bowl years of the 1930s.
President Anote Tong of Kiribati asked the international community this month to start thinking of ways to help entire nations relocate to higher ground. He called for an international fund to buy land for such mass migrations and said his nation's citizens are prepared to pay for a new homeland. Many citizens of Kiribati are attempting to migrate to New Zealand, and Tong said he is arming his people with skills in vocations such as plumbing that would be valuable in other countries.