Host countries will be increasingly unable to accommodate fast-growing throngs of refugees who will breach national borders wholesale. However many countries may wish to seal themselves off from refugees, they will find they cannot do so. It has proven impossible for the United States to contain the movement northwards of Mexicans and other Hispanics across the long southern frontier. In Europe, front-line countries, notably Spain, Italy and Greece, are showing themselves to be largely powerless to keep out increasing numbers of migrants from across the Mediterranean. There will be other problems.
Refugees often come from a home environment different from that in which they seek sanctuary.
They bring alien customs, dietary preferences and religious practices. They tend to congregate in destitute sections of such megacities as Dhaka, Calcutta, Karachi, Lagos, Sao Paulo, Lima and Mexico City. In these localities, they depend on city services that are already over-loaded. Or they are obliged to crowd into refugee camps with grossly inadequate subsistence conditions. Resettlement of refugees is never easy and assimilation is rare.