There are about 184 million migrants in the world, with almost half of them living in low- and middle-income countries. Sixty-two million migrants are predicted in the next century.
The populations of high-income and many middle-income countries are quickly aging, Özden added.
“This is the only time in human history where the populations of the countries are declining voluntarily,” Özden said. “People are deciding not to have children. Demographic trends are rapidly changing and will change.”